A Normal Spinal Position: It's Time to Accept the Evidence

623

A Normal Spinal Position: It’s Time to Accept the Evidence

INTRODUCTIONRecent trends in our chiropractic profes-

sion seem to be leading away from well-ness care into an exclusive focus on short-term care for relief of symptoms, especiallypain.1 In contrast, some recent articlesauthored by CBP Nonprofit, Inc, researchersexpress an interest in spinal reconstruction,structural outcomes, and care beyond the mererelief of symptoms.2-6 In a recent commentary, Haas etal7 have taken exception to this approach.

A commentary by Haas et al7 concerning one of ourrecent papers8 expressed a paradigm for chiropractic scienceand patient treatment that is different from that expressed inour recent literature reviews and original publications. Theirviews on normal spinal position, radiograph usage, radi-ograph reliability, and spinal rehabilitation of normal struc-ture, as expressed in their commentary, did not includemechanical engineering principles, which we believe neces-sary for understanding the stresses and strains in abnormalor asymmetric loading of spinal tissues.

In 1998, we had discussed a number critical flaws in 8commonly held beliefs espoused by some diplomate chiro-practic radiologists.8 Thus, given the fact that the “conven-tional wisdom” of chiropractic radiologists was challenged,it was not surprising that there were a total of 8 authors andconsultants who contributed to the rebuttal commentary ofHaas et al.7 What was not expected was the divergence into acritical analysis of Chiropractic Biophysics (CBP) methodsand the Harrison spinal model,9 which is used as an anatom-ical outcome for patients receiving CBP-based treatment.However, we are pleased to both address those raised con-cerns and present our rebuttal to Haas et al’s misconceptionsabout the use of radiography in chiropractic clinical practice.

Because this normal spinal model was only self-publisheduntil 1992,10-12 some have denied the existence of theHarrison normal spinal model and its implications for physi-ology. These implications were discussed in a short reviewof Wolff’s law (bone remodels to stress) and Davis’ law (softtissue remodels to stress) for abnormal sagittal spinal config-urations.3 Because this Harrison model has recently beenpublished in the indexed literature,13-19 its existence can nolonger be denied or ignored.

Inasmuch as Haas et al7 had many differenttopics in their commentary and did providesection titles, it is convenient to respondwith reference to those section titles. It isnoted that some of their section titles are

obscure and certainly not mainstream (eg,their reference to Sackett); nonetheless, the

titles are useful as objects for debate. First,however, we present a logical approach to move-

ments in upright posture, from which much about a nor-mal upright position can immediately be derived.

It is a basic theorem of physics and engineering that themovement of any object can be decomposed into rotation,translation, and deformation.20 Whereas White and Panjabi21

have used this theorem to describe the 6 degrees of freedom(DOF) of individual spinal segments (rigid bodies), we haveused this theorem to express all possible movements of thehuman head, thoracic cage, and pelvis in 3 dimensions.10-11

Figs 1 and 2 are reprinted from a previous article in theJournal of Manipulative and Physiological Therapeutics.22

These movements will form the basis on which we illumi-nate a normal postural position.

After providing a review of normal upright position interms of the engineering principles and literature reviews tobe presented below, analysis of chiropractic manipulations(which are mostly torsional loads) will lead the reader to con-clude that diversified manipulation is inadequate for obtain-ing a structural change in the neutral resting posture. Thus,precise postural setups (such as those used in the CBP tech-nique) are recommended for the sake of obtaining structuralcorrection in a patient’s spine after the relief of symptoms.

Biologic Plausibility and ValidityHaas et al1 defined “biologic plausibility” for us. They

appear to have assumed that the only important “biologicprocess” is back pain, and on the basis of that view theyassume that it is unnecessary to address the upright spinalconfiguration under gravity. In addition, they state that ourmodel is “merely a mathematical description of optimalstress on a static system”.7 We now reply that back pain is amultifactorial condition. The process of spinal degenerationand abnormal biomechanics’ causing mechanical distor-tions of the central nervous system (CNS) is better charac-terized as a degenerative disease process. Thus, symptomsappear after the disease process is well advanced (as is the

Journal of Manipulative and Physiological TherapeuticsVolume 23 • Number 9 • November/December 2000

0161-4754/2000/$12.00 + 0 76/1/110941 © 2000 JMPT

COMMENTARY

doi:10.1067/mmt.2000.110941

Journal of Manipulative and Physiological TherapeuticsVolume 23 • Number 9 • November/December 2000Commentary • Harrison et al

624

case in heart disease, cancer, and hypertension). In suchprocesses, the emphasis is placed on controlling risk fac-tors. It is suggested that optimizing the spine’s position toresist the compressive force of gravity is a logical place atwhich to address an “optimal stress” risk factor. Of course,

the entire oculovestibular, muscle spindle, and mechanore-ceptor systems perform this function from moment tomoment in upright stance. To imply that this is an unimpor-tant subject regarding spinal mechanics is to ignore a majorfunction of the CNS.

Fig 1. Rotational DOF of global body parts.


Commentary • Harrison et al

625

Haas et al7 believe that there is no compelling evidence toindicate that subluxation exists. However, subluxation hasbeen precisely defined through use of deviations from normalupright posture and our normal spinal model.23 In addition,Haas et al do not appear to appreciate the concept of model-

ing the spine. A model is used to predict nature; it is a tool.Our model’s usefulness will be determined in future studiesof clinical significance. For such studies to be carried out,the parameters of the model’s usage must first be established,and one of these parameters is a measurement method—ie,

Fig 2. Translational DOF of global body parts.


626

posture and radiography. Therefore, determining the reliabili-ty of the radiographic markings (and posture reliability) is alogical first step. Haas et al claim that we cannot address“clinically meaningful conditions,” but they want to stop usfrom attempting such future research by negating ourattempts to study the reliability of our methods at the begin-ning. Clinical significance can be determined only after onehas precise definitions to test and only after one has reliabili-ty data established for the measuring methods.

Because a normal postural position (outside alignment)and a normal spinal position (inside alignment) are funda-mental to our approach to “controlling risk factors” for spinaldysfunction, a review pertaining to each of these ideas is pro-vided to enable the reader to determine whether Haas et al’sparadigm matches the biomechanical/biomedical literature.

Normal Upright PostureThere are at least 3 approaches by which one can immedi-

ately discover a normal spinal alignment in the anteroposteri-or (AP) view and the lateral view. Most rigorously, equilibri-um equations in the AP view can be used to prove that thepostures of ±Tx, ±Ry, and ±Rz in Figs 1 and 2 result in abnor-mal asymmetric loads on the spinal tissues and lower extrem-ities when these postures are in the neutral resting posture ofthe subject under investigation. These postures are also asso-

ciated with asymmetric muscle efforts. Numerous elec-tromyographic studies over the past 4 decades add supportfor this fact.24-34 Because many clinicians7 may be unfamiliarwith engineering principles and aspects of upright humanstance, 2 other “proofs” are presented.

As a first discussion of normal posture, the readers andHaas et al7 are asked to consider that all chiropractic, osteo-pathic, physical therapy, and medical colleges teach a plumbline analysis and global ranges of motion, as depicted for±Tx, ±Ry, and ±Rz in Figs 1 and 2. With regard to the AP view,the following 3 questions come immediately to mind: (1)axial rotation to the left and to the right—from where? (2)lateral flexion to the left and to the right—from where? (3)lateral translation to the left and to the right—from where?

Before trying to give an answer that is different from ver-tical alignment in the AP view, recall that these main postur-al motions of the head and thoracic cage, ±Tx, ±Ry, and ±Rz,cause spinal coupling patterns for which the movements areknown.22,23,35,36 These vertebral coupling patterns arealways described as movement away from a vertical normalspinal alignment. Our research team is the first to reportspinal coupling for ±Tx of the head and thoracic cage.35,36

Some authors have argued that slight deviations of theupper thoracic spine are correlated to the side of the domi-nant arm37 and that a true vertical spine in the AP view there-

Fig 3. A, Vertical position of normal AP posture as agreed on in literature. B, D, Proposed ideal lateral postures. C, Average lateralposture. Note that differences between Fig 3, B and Fig 3, C are slight.

A B C D



627

fore cannot be considered normal. Either sight deviationscan be ignored because of the minimal amount of asymmet-ric loading, or unilateral upper extremity exercises on thenondominant side can be prescribed to correct these. Inaddition, Haas et al7 claim that because of the natural asym-metry of the spinous processes, the sensibility of a true verti-cal spine in the AP view is questionable. However, morethan 2 decades ago, Farfan38 found that the entire vertebralarchitecture in the lumbar spine will change and keep thelamina junction in line with the structural center of the verte-bral body. This means that the center of mass will remainapproximately the same. Farfan38 writes (pages 34-5): “Itwould appear that in the development of the vertebra, asym-metrical body growth is compensated for by asymmetricgrowth of the neural arch.” Therefore, the centers of mass inthe AP view will still be in line with vertical gravity to mini-mize loads on the spinal tissues and to be the origin positionfor postural movements.39-47

Recently, Kiefer et al48 showed that T1, T12, and S1 mustbe vertically aligned in the lateral view. In the lateral view,the previous argument can be applied to the movements of±Rx, ±Ty, and ±Tz in Figs 1 and 2. In fact, much research hasbeen conducted on sagittal posture, especially anterior headtranslation (+Tz) and pelvic posture, by physical therapists.49-

61 This research indicates that anterior head translation (pro-trusion) is fundamentally accepted as abnormal and that, ingeneral, posture evaluation is repeatable and reliable.

For a second analysis, a statistical evaluation is present-ed. As always, there is debate in the literature concerningaverage normal and ideal normal (upright posture).However, the differences in these upright positions aresmall. In 1973 and 1975, Beck and Killus62,63 used a com-puter analysis to average upright lateral and upright APpostures of several hundred young adults. They reportedon the reliability of their digitizing methods and showedthat posture was reproducible “even though the x-rayswere taken years apart.” They critically analyzed all of theprevious reports of posture (such as those of Staffel,64

Goff,65 Leger,66 Haglund,67 Osgood,68 and Wiles &Lond,69 which include such terms as flat back, roundback, and hollow back). Beck and Killus62 found highlypathologic postures, small sample sizes, incorrectlyapplied statistics, and lack of an origin for measurementincluded in previous categories of posture. Using a digi-tizer, they plotted, in graphic form, the coordinates (paths)of the vertebral bodies of all subjects in the AP and lateralviews. With 1500 subjects in their 1975 report,63 theynoted that they had “one normal distribution in every pointof abscissa.” They write:

It follows that there is only one ideal type of spinal col-umn. According to our findings the theory of constitutionaltypes (of posture) cannot be confirmed.62

Beck and Killus provided separate graphs of their maxi-mum points of their normal distributions of posture. Thespine had the 3 spinal curves with vertical alignment of T1,T12, and S1 in the lateral view.

Therefore, the vertical alignment of the global centersof mass in upright posture in both the AP and lateral viewshas been statistically established for young adults. Fig 3illustrates this alignment with some additional referencesapplied to the location of the shoulders and lower extrem-ities.

Harrison Spinal ModelThrough use of multiple studies and normal distributions

with an ideal mean normal center, normal upright posturehas been defined in the literature. This normal posture in theAP view correlates with a straight (vertically aligned) spine.In the lateral view of upright normal posture, it is generallyaccepted that there exist a cervical lordosis, a thoracickyphosis, and a lumbar lordosis; however, neither the over-all sagittal curvatures of the cervical, thoracic, and lumbarareas nor the segmental contributions are generally stated oragreed on. Therefore, when normality is being debated, onlythe overall geometric shape and segmental angulation of thecervical, thoracic, and lumbar sagittal curvatures are open todebate.

This is where our normal Harrison Spinal Model entersthe literature. Both our average (400 subjects) and our idealnormal sagittal cervical spine models were published in1996.14 Our average (derived from 552 subjects) normallumbar model was published in 1997.18 Our ideal normallumbar model was published in 1998.13

At this point, it is important to point out that theHarrison Spinal Model is the normal path of the posteriorlongitudinal ligament along the posterior vertebral bodies.This ideal and statistical average model has a mean and arandom error component (variation around the mean). It isa model not of the entire anatomy of the spine but only ofthe curvature in the sagittal plane. Models of the entirespine require huge computer codes in which finite ele-ments methods are used.

The paradigm presented by Haas et al7—that abnormalposture has no effect on physiology—is quite puzzling. It iswell documented that abnormal spinal loads (forces andmoments) over time cause pathoses. This is taught in all chi-ropractic college physiology courses as Wolff’s law (boneremodels to stress) and Davis’ law (soft tissues remodel tostress).

In the light of the foregoing preceding background dataand ideas, a response to each of Haas et al’s topics7 can nowbe presented.

Clinical Sensibility and ValidityCervical kyphosis is not a normal variant. In their commentary,

Haas et al7 repeat the common misconception that cervi-cal kyphosis is a normal variant. In general, the studiescited by Haas et al7 are inadequate, being characterizedby inappropriate methods, flawed statistical analysis (ifany), and/or unsupported conclusions. It is our intent toreview the 6 studies70-75 mentioned by Haas et al and topresent an updated literature review focused on cervicalkyphosis.


628

To begin, Haas et al7 refer to a 1986 study by Gore et al.70

In 200 randomly selected asymptomatic subjects, Gore et alfound an average of 22 degrees of lordosis using RuthJackson’s angle from C2-C7; they found that a minority(9%) of these subjects demonstrated the presence of a cervi-cal kyphosis. In contrast, Harrison et al76 found that 35% of250 symptomatic subjects had kyphotic deformities. Thesedata indicate a dramatic increase in cervical kyphosis insymptomatic subjects in comparison with asymptomaticsubjects. An additional concern is the cross-sectional studydesign used by Gore et al. It is common knowledge amonghealth care providers that several life-threatening illnessesand diseases remain asymptomatic throughout their courseor are associated with no overt signs or symptoms until theend stages. Harrison et al3 have previously reviewed theshortcomings of the study by Gore et al.70

The second article used by Haas et al7 in their assertionthat kyphosis is a normal variant is the study by Maimaris etal,71 who retrospectively assessed 67 asymptomatic and 35symptomatic whiplash-injured patients. Follow-up wasattained an average of 2 years after the injury. Maimaris et alconcluded that “reversal of the cervical spine to a kyphoticposition was not associated with prolonged disability."However, there are several problems with this study. First,only 39 (58%) of the 67 asymptomatic subjects were "clini-cally examined," whereas 30 (86%) of the 35 symptomaticsubjects were examined. This is a large difference in the per-centage of subjects examined in each group, and it can leadto inaccurate data analysis between the groups. Second, thelateral cervical spine radiographs were not measured andquantified; they were merely classified into lordotic, straight,or kyphotic. Therefore, no quantifiable statistical analysiswas performed to actually address the issue of the amount ortype of lateral cervical curvature as it relates to the presenceof symptoms. As an example, on page 396, Maimaris et alpresent two figures, one representing a kyphotic cervicalcurve and the other representing "loss of the normal lordo-sis." If one looks at these two radiographs, it is readilyapparent that both of these are kyphotic curvatures. Last, intheir Table III on page 395, Maimaris et al present the per-centage of subjects in each group with radiographic abnor-malities. Clinically significant differences are noted betweenthe symptomatic and asymptomatic groups, with the symp-tomatic group having higher percentages of straight andkyphotic curves and the asymptomatic group having thehighest percentage of lordotic curves.

Similarly, Haas et al7 make the claim that Pedersen72

“observed that cervical hypolordsis may be a normal vari-ant.” However, the study by Pedersen is of insufficient quali-ty for the drawing of such a conclusion. Pedersen compareda “treatment” group of only 9 patients with a “control” groupof 17 patients. The criterion for inclusion in the controlgroup was as follows: “The subject must not have had anyhistory of cervical or cervico-thoracic symptoms prior to 2months before entry (lasting continuously for more than 3weeks).” This designation was a poor choice, inasmuch assubjects in the control group could either have had pain of

less than 3 weeks’ duration before the past 2 months or hadpain in the 2-month period immediately before the study. Inaddition, the sample size was extremely small and subjectsin the two groups were not matched for age, weight, height,or sex.

Furthermore, Haas et al7 state that “in a study of 180 sub-jects, Borden et al concluded that a straight cervical spine isabnormal only in conjunction with decreased cervical flexi-bility.” In actuality, the study by Borden et al73 found that of180 asymptomatic subjects, 3 (1.7%) had a reversed cervicalcurve and 13 (7.2%) had a straight cervical spine. Of the 13subjects with a straight cervical spine, 11 (85.0%) had con-comitant degenerative changes. In the 3 subjects with cervi-cal kyphosis, “there were generalized hypertrophic degener-ative changes and fusion.”73 Borden et al concluded that“roentgenographically demonstrated loss of the cervicalcurve, combined with normal thoracic kyphosis and lumbarlordosis, may be indicative of abnormality of the cervicalspine.”73 In the light of this information, one might wonderhow Haas et al7 could possibly believe that this referencesupports the position that cervical hypolordosis or kyphosisis a normal variant. Perhaps they were performing secondaryreferencing and did not read the original paper.

Likewise, Haas et al7 believe that the study by Marshalland Tuchin74 indicates “that spinal curve alteration itselfmay not require treatment.” However, there are severalpotential problems with the method used by Marshall andTuchin.74 The most serious of these is their choice of the C1-C7 Cobb angle for lateral cervical curve mensuration. The 4-line C1-C7 Cobb angle is not a valid representation of thecervical lordosis.8,77 Therefore, without a segmental analy-sis, no conclusions can be made concerning the shape and/ormagnitude of the cervical lordosis and its clinical signifi-cance in that study.

Last, Haas et al7 rely on the conclusions of Gay.75 In a1993 review, Gay concluded that cervical kyphosis is a nor-mal variant. However, before Haas et al’s7 commentary, thevast majority of the references cited by Gay had previouslybeen critically analyzed and had been found to be inappro-priate by us in 1998.8 Thus, no weight can be applied toGay’s75 review.

Recent and past mechanical, clinical, and surgical studiesconcerning the cervical lordosis do not support the positionthat cervical kyphosis is a normal variant. Haas et al7 seemto insinuate that the only supporting reference that we8

offered for the clinical significance of a normal cervical lor-dosis was by Cote et al78 (our old reference 1). This clearlywas not the case (see references 9-17 in our original manu-script8). However, because Haas et al and many others con-tinue to debate this issue, a thorough review of the literatureon cervical kyphosis and its effects is presented here.

It is relevant that several studies have investigated andlinked altered cervical curve configurations to the presenceof chronic headache pain.79-81 In a survey of more than 6000cases of chronic headache-sufferers, Braaf and Rosner79

found that “complete or segmental loss or reversal of thenormal lordotic curve of the cervical spine is the most con-



629

sistent characteristic feature and very often is the onlyabnormality found.” In 47 subjects with tension andmigraine headaches, Vernon et al80 found a high incidenceof hypolordosis, straightened cervical curve configurations,and reversed cervical curve configurations. Nagasawa et al81

compared 372 patients with tension headaches and 225 con-trol subjects matched for age and sex; they found statistical-ly significant differences between the two groups, theheadache patients having straightened cervical curve config-urations and low set shoulders. In addition, with increasingage, the headache patients’ cervical curve was straight morefrequently. This information contrasts nicely with the find-ings of Gore et al,70 who noted that in asymptomatic sub-jects, the cervical curve increased with age.

Looking into the matter further, we note that when poor out-comes after surgery are considered, several studies have founda good cervical lordosis to be a significant factor in preventingneurologic deficit and/or compromise.82-93 For example, Gotoand Kita82 state that “postoperative kyphotic malalignment orangulation are factors strongly affecting the outcome ofsurgery.” Yamazaki et al83 compared 2 groups of patients withossification of the posterior longitudinal ligament (PLL) post-operatively. Group I consisted of patients with no anterior“compression” of the spinal cord, and group II comprisedpatients with residual cord “compression.” The investigatorsfound a lordosis of less than 10.0 degrees or cervical kyphosiscorrelated with the presence of postoperative spinal cord com-pression; this result was statistically significant.

Similarly, recent surgical studies have emphasized thatoperations that leave the patients’ cervical spines with lesslordosis are associated with increased neck, upper thoracic,and shoulder pain and overall poorer health outcomes.94-97

Lowry94 used the average lordosis of 22 degrees found byGore et al70 to gauge a successful surgical outcome; heclaimed that “a fixed kyphotic posture of the mid-cervicalspine will lead to overall sagittal imbalance manifested byaxial pain in the upper to mid-thoracic region as well as inthe posterior cervical spine.” Katsuura et al95 compared 44cases treated with anterior cervical plating (a method ofensuring a stable lordotic correction) to 30 patients receiv-ing anterior fusion without plating. These patients were fol-lowed for an average of 38 months postoperatively. Themagnitude of cervical lordosis was assessed through use ofRuth Jackson’s angle (posterior tangents from C2-C7), andintersegmental (2-line) Cobb angles were used for the align-ment of the fused segments. Katsuura et al found statistical-ly significant differences in the incidence of neck painbetween the two groups, the plated group having less neckpain and a statistically significant increase in cervical lordo-sis. Likewise, Kawakami et al96 retrospectively evaluated 60patients postsurgically. Cervical lordosis was measured witha 4-line Cobb’s method from C2-C7 and a segmental (2-line) Cobb angle at the fused level. Segmental kyphosis atthe level of the fusion and less lordotic curvature were foundto statistically predict which patients would develop “axialsymptoms” (neck pain, shoulder pain, and/or stiff neck).The use of 2-line Cobb methods rather than the 4-line Cobb

method is important because the standard error of measure-ment (SEM) is much lower (<3) and the segmental analysisfinds alterations within the curve—ie, it is not just evalua-tion of the end segments.

According to Haas et al,7 the surgical studies just cited,all of which indicate the clinical significance of the cervicallordosis, are not appropriate because surgical patients are“not typical chiropractic patients who require conservativecare.” But perhaps this is merely an excuse for not acceptingthe facts.

However, there are several nonsurgical studies indicatingcervical kyphosis as a factor predictive of poor results.98-100

In a long-term follow-up of 146 whiplash-injured patients,Hohl98 identified cervical kyphosis as factor predicting apoor outcome. Norris and Watt99 followed 61 patientsinvolved in motor vehicle accidents for a minimum of 6months; they found abnormal neck curves to be “more com-mon in patients with a poor outcome.”99

In addition to clinical outcomes of pain and neurologicdeficits, several papers focusing on cervical biomechanicsindicate that cervical kyphosis is abnormal.101-103 Using anengineering analysis of slope and bending moment,Matsunaga et al101 proved that degeneration and consequentsubluxation will develop in abnormal kyphotic configura-tions, which they termed buckling alignments. “In the caseof the S-shaped spine,” they write, “the spine is in a ‘buck-ling’ condition, which corresponds to an unreasonable sup-porting function.”

With regard to ossification of the PLL, Matsunaga et al102

followed 101 patients for a 5-year period. Using an engi-neering analysis of strain, they found that ossification ofPLL progressed in the areas showing uneven and abnormalstrain at the adjacent intervertebral disk and PLL. Spe-cifically, strain in the tensile direction was found to corre-late with ossification of the PLL. It is important to note thatthe only way to increase the tensile strain in the PLL is tohave concomitant hypolordosis or kyphosis.104

Several other studies have indicated that loss of cervicallordosis or kyphosis is a cause of or is associated with ahigh incidence of degenerative changes in the disk and ver-tebral bodies.70,73,98,105 Because degenerative changes of thecervical spine are a known cause of morbidity,98,99,106 it canbe stated with confidence that cervical kyphosis is not a nor-mal variant.

In a recent 1997 text on the spine, statements byFrymoyer et al109 are clinically significant about cervicalkyphosis as a normal variant. In fact, they assert that“kyphosis, straightening, and hyperlordosis of the cervicalspine may all be seen in conjunction with spondyloticmyelopathy, whereas in other patients the normal curvatureis preserved” and that “kyphosis and hyperlordosis maycoexist and thus this gives rise to an S-shaped deformity ofthe spine, causing greater instability and management prob-lems.”109 Furthermore, in a 1996 review on the cervicalspine surgeries, Lowery94 states that “an additional featureof any plate system, whether anterior or posterior, should beto establish a lordotic cervical curvature.” The evidence


630

against76-107 cervical kyphosis as a normal variant far out-weighs the evidence to the contrary.7,70-75

Finally, with regard to the cervical spine, it is noted thatmany authors (including Haas et al) have neglected to inves-tigate cervical lordosis and child development. It should nothave been necessary to present the preceding review indicat-ing that cervical kyphosis is not a normal variant, inasmuchas Bagnall et al108 showed in 1977 that the cervical lordoticcurve is formed in intrauterine life (9.5 weeks). Cervical lor-dosis could thus be considered a primary curve, like the tho-racic kyphosis. Any loss of cervical lordosis is due to trau-ma, repetitive play, or work postural loadings during and/orafter birth. Importantly, using skin markers or surface visual-ization does not correlate with the shape, magnitude, ordirection of the sagittal cervical spine.109,110 Therefore, theuse of radiography for identification of any abnormal lateralcervical configuration is absolutely mandatory.

Thoracic KyphosisIn addition to the work of Beck and Killus,62 whose nor-

mal graph used a statistical average, multiple studies haveinvestigated thoracic kyphosis. As in cervical skin contourversus radiographic measurements, D’Osualdo et al111 foundconsiderable disagreement between radiographic findingsand results obtained with an Arcometer. In 1983, Willner andJohnson112 used spinal pantographs based on skin contour tosuggest that kyphosis varied in girls and boys. However,using an ISIS scanner for evaluating back shape, Carr et al113

reported no statistically significant differences with respectto age and sex in children, no statistically significant differ-ences with respect to age and sex in adults, and no differ-ences between children and adults. Using radiography,Voutsinas and MacEwen114 reported in 1986 that “the differ-ences between boys and girls were not significant in anygroup.”

Some studies have reported a large range of values forthoracic kyphosis—from 20 degrees to 40 degrees.115-120

One problem in deciphering a normal average thoracickyphosis is the inability to see T1-T4 on most lateral tho-racic views; this has caused different levels of Cobb angleanalysis in the literature—with different angles of kyphosis,of course. For example, the following levels have been used:T5-T12, T4-T12, T3-T12, T2-T12, and T1-T12. This causeswide ranges of values. For example, Propst-Proctor andBleck117 measured the inferior endplate of T5 to the superiorendplate of T12 in 104 normal children who were referredfor suspected screening of scoliosis; they reported a normaldistribution with a range of 21 to 33 degrees and a mean of27 degrees.

In 22 cases, Singer et al120 reported no difference in tho-racic kyphosis in subjects before and after death (T4-T12:~49 degrees).120 Milne and Williamson121 reported no sig-nificant change in thoracic curvature on follow-up radi-ographs of 261 subjects aged 62-90 years. In 99 Greek menand women, Korovessis et al122 reported that thoracic kypho-sis was not gender related, though kyphosis was found toincrease with age (mean T4-T12: ~36 ± 9 degrees). In 102

subjects, Bernhardt and Bridwell123 reported a mean Cobbfor T3-T12 of ~36 degrees and a mean Cobb for T1-T12 of~40 degrees. Jackson and McManus124 investigated sagittalbalance in 100 patients and 100 volunteers; they reported thesame means and ranges for males and females and forpatients and volunteers (mean T1-T12: ~43 ± 9 degrees). In1998, Vedantam et al125 investigated standing sagittal align-ment in 88 adolescents (aged 10-18 years); they reported a“striking similarity in regional thoracic kyphosis and lumbarlordosis between adolescents and adults.”

In 1980, Fon et al126 reported that in 316 subjects, thoracickyphosis increased with age. In 1993, Cutler et al127 reportedthat hyperkyphosis in women was associated with alteredvertebral body shape (anterior wedging), loss of bone densi-ty, loss of fitness, decreased muscle strength, and reducedsurvival; the investigators suggested a correlation betweenabnormal upright thoracic posture and changing architectureof the spinal column (Wolff’s law). In 1996, Kolessar et al128

reported that 69 patients had kyphotic Cobb T5-T12 mea-surements of >33 degrees, whereas all 24 volunteers hadCobb T5-T12 < 33 degrees.

It is interesting to note that studies on thoracic kyphosiswith large population groups provide nearly normal distri-butions. Thus, as noted by Beck and Killus,62-63 statisticallythere would be one ideal normal at the mean of these distrib-utions. With the few reported values for Cobb T1-T12 andwith ratios of values from Cobb T2-T12, T3-T12, T4-T12,and T5-T12, the mean thoracic kyphotic value seems to bebetween 40 and 50 degrees for a Cobb angle from the top ofT1 to the bottom endplate of T12.

Lumbar LordosisHaas et al7 have neglected a large body of literature sup-

porting the clinical significance of a normal lumbar lordo-sis.13,18,19,116,129-158 To date, there have been 10 separatestudies in which a similar method was used to investigatethe normal shape and magnitude of the human lumbar lor-dosis.18,115-117,122,129-133 These 10 studies used strict criteriain categorizing men and women as normal subjects. Theage range for the subjects was large—between 10 and 80years of age. All 10 of these investigations used radi-ographic analysis in the neutral upright posture, and totalas well as segmental lumbar lordotic angles were mea-sured. In all, a total of 755 normal subjects from 10 sepa-rate studies were included in the analysis. All of these stud-ies18,115-117,122,129-133 indicate that the upper lumbar curve,T12-L3, is minimally lordotic whereas the distal lumbarcurve, L4-S1, accounts for approximately 65.0% of thelumbar lordosis.

Haas et al7 claim (believe) that different patient popula-tions (races) have different optimal spinal configurations andthat “given the natural variation and asymmetry in thehuman musculoskeletal system,” an ideal spinal model is notplausible.

Their beliefs are not supported by recent anthropometricclinical and experimental data on the lumbar spine. For exam-ple, several studies addressing the shape and magnitude of the



631

lumbar lordosis found no differences with respect to geo-graphic location and/or ethnicity.133-137 In a radiographicstudy of the lumbar lordosis in 16 healthy Chinese men,Chen133 concluded that “no obvious interracial differenceswere found in the geometric data found in this study.”Mosner et al134 compared the lumbar lordotic spinal radi-ographs of 25 black women with those of 27 white women;no significant differences were found in the lumbar lordosis,as measured with spinal radiographs, though differenceswere found in external skin contours. This difference in skincontour “gives a false impression of increased lumbar lordo-sis”134 in black versus white women. In a 1985 study of 973adults, Fernand and Fox135 reported that “black and whitepopulations demonstrated no significant difference in themean lumbar lordotic angle.” Korovessis et al136 studied thesagittal configuration of the lumbar spine in 120 asympto-matic Greek volunteers. “We have shown that there are nodifferences in the sagittal profile across geographicallyand ethnically different populations,” they write. As regardsthe “natural variation” of human anatomy, Janik et al13 haveshown that reported small differences in vertebralbody–to–disk height ratios, found in different studies, haveno effect on their elliptical model of the lumbar lordosis (ie,none of the segmental angles, T12-S1, were found to changemore than 1 degree).

As regards low back pain and lumbar lordosis, 6 separatestudies have found statistically significant differencesbetween patients with low back pain and matched normalcontrol subjects.19,136,138-141 Korovessis et al136 comparedhomogenous groups of 120 volunteers and 120 patients withchronic low back pain; subjects were matched for age, sex,and ethnicity. Lordosis was measured through use of a 4-lineCobb’s method from T12 to S1, and segmental angles (2-lineCobb) were measured through use of endplate lines relativeto horizontal. Statistically significant differences were foundbetween the two groups, the chronic low back pain subjectshaving a decreased distal lordosis, L4-S1, in comparisonwith the controls.

Harrison et al19 used elliptical modeling to discriminatebetween a rigorously defined normal group and 3 separategroups of patients with low back pain; that study included(1) 50 normal subjects from a pre-employment physicalscreening, (2) 50 patients with acute low back pain (firstoccurrence; less than 6 weeks’ duration), (3) 50 patients withchronic low back pain (pain of more than 6 weeks’ durationor a history of recurrent disabling low back pain), and (4) 24subjects with low back pain and radiographically verifieddegenerative disorders or pathoses. These 4 groups werematched for age, weight, height, and sex. The investigatorsfound that “of 11 angles, 2 distances, and 2 ratios, statisticalanalysis was significantly different across groups for 12 ofthese measurements.”19 The chronic low back pain and lum-bar pathosis group had a decreased lordosis, whereas theacute low back pain group had an increased lordosis in com-parison with the normal subjects.

In a similar study, Jackson et al138 compared sagittal lum-bar radiographs of 50 normal volunteers with those of 50

adult patients with symptomatic degenerative lumbar diskdisease, 30 patients with low-grade L5-S1 isthmic spondy-lolisthesis, and 30 patients with idiopathic or degenerativescoliosis. Again, statistically significant differencesbetween the groups were found in the radiographic mea-surements.138

Adams et al142 followed 403 volunteer health care work-ers for a 3-year period. A decreased lumbar lordosis wasfound to be one of the personal risk factors in predisposingsubjects to a first-time episode of low back pain requiringmedical evaluation. Itoi143 analyzed lateral lumbar radi-ographs in 100 postmenopausal female patients with spinalosteoporosis; a statistically significant increase in low backpain was found in patients with a rounded thoracic spineand lower acute lumbar kyphosis. This lower lumbar kypho-sis has been shown to cause an increase in low back pain,perhaps as a result of increased electromyographic activityof the paraspinal musculature.144

Many surgical papers have identified both lumbar hyper-lordosis145 and hypolordosis or kyphosis146-152 as risk fac-tors for low back pain requiring surgical correction. Last,several investigators have found statistically significantincreases or associations between loss of lumbar lordosisand degeneration of the disk, vertebral body, and lig-aments.152-156

With regard to lumbar lordosis, most experts agree that“the assessment of spinal curvature is a part of an evalua-tion in patients with back problems”.157 Because surfacemeasurement of spinal curvature represents neither seg-mental nor total lumbar lordotic alignment, radiographicanalysis is a mandatory part of the routine examination ofthe lumbar spine.134,158 We believe that Haas et al’s7 nega-tion of the importance of the structural alignment of thespine stems from a neglect of mathematics and engineeringanalysis. They seem to be reading published papers withjust rudimentary 4-line Cobb angle geometry while ignor-ing papers that analyze spinal alignment with a slightlyhigher level of mathematics. Papers that use segmentalanalysis (see the references above), some analytic geome-try,13,19 calculus,103,120,153 curve fitting,9,159-161 and finiteelements162-164 have shown the importance of normalalignment of the spine.

Pelvis OrientationPlaugher et al165 have investigated pelvic radiographic

measurements and found reproducibility in pelvic position-ing and radiographic marking. Troyanovich et al166 haveestablished high intraclass coefficients (ICCs) and lowSEMs for pelvic tilt on the lateral lumbopelvic view.Jackson et al138 have reported high Pearson correlationcoefficients for pelvic measurements (in degrees) on lateralfull spine views; they reported significant differences inpelvic measurements for normal subjects versus 3 patientgroups.

In 1995, Saji et al167 studied 61 adolescents with idio-pathic scoliosis and 33 normal subjects for femoral neckshaft angles and asymmetry of the hips. An angle was


632

formed by lines through the femoral shaft and neck. Intra-observer and interobserver reliability were assessed. Therewere no significant differences between the measurementsof a single observer or between the measurements of differ-ent observers. Standard errors of measurement were small(intraobserver, 1.6 degrees; interobserver, 1.9 degrees). Sajiet al discovered that a normal femoral neck-shaft angle wasapproximately 135 degrees, the scoliosis subjects having amuch higher value for this angle (straightened femur).

Levine and Whittle168 studied the effects of pelvic tilt onlumbar lordosis. They reported that flexion of the pelvisincreased lumbar lordosis and that extension of the pelviswas associated with hypolordosis. Similarly, Harrison et al19

reported that their subjects with acute low back pain hadflexed pelvises and lumbar hyperlordosis whereas their sub-jects with chronic pain had extended pelvic positions andlumbar hypolordosis.

ReliabilityHaas et al7 make the following statement: “To date, there

is little convincing evidence for the reliability of radiograph-

ic analysis of spinal displacement.” We have published 5radiographic line drawing analysis reliability studies andhave another in review.77,166,169-172 In other chiropractic pub-lications, the reliability of line drawing analysis on the nasi-um view and pelvis, additional AP, and lateral views havebeen reported.165,173-176 Curiously, in regard to the nasiumand AP lumbopelvic radiographic views, Haas et al make thefollowing inaccurate statement: “There are no grounds forgeneralizing from studies on pelvic height and the craniumto the repeatability of analyzing spinal curves and segmentaldisplacement.”7 Perhaps Haas et al are unaware that the nasi-um radiograph includes the cervical spine and that its align-ment in comparison with the “cranium” has been subjectedto several reliability studies.173,174

For the various Cobb methods (2-line and 4-line), numer-ous reliability studies have been done on AP lumbar, AP tho-racolumbar, and AP thoracic, lateral lumbar, lateral thoracic,and lateral cervical views.9,159-161,177-192 Furthermore, themeasurement of pelvic rotation and sagittal segmental trans-lations has been reported as reliable.193-195 In 1992, Capassoet al196 reported high Pearson correlation (r > 0.90) for both

Standard error of measurement (degrees)

ICC 4-line Cobb 2-line Cobb Mod. Risser-Ferg Post. tangentArea/Reference Intra Inter Intra Inter Intra Inter Intra Inter Intra Inter

AP cervical — — — — — — — — — —Troyanovich et al >0.90 >0.90 — — — — <2.0 <1.5 — —

AP thoracic — — — — — — — — — —Pruijs et al (1994) (Spearman > 0.98) — 3.2, 2.0* — — — — — —Sevastikoglou, Bergquist — — — 3.1 — — — — — —Beekman, Hall — — — 4.2* — — — — — —Gross et al (p176) — — 3.2 2.3 — — — — — —Morrissy et al — — 4.9, 3.8, 7.2, 6.3, — — — — — —

2.8 6.3Carman et al — — — 3.8* — — — — — —Goldberg et al — — 1.9 2.5 — — — — — —Desmet et al — — — 1.1, 1.3* — — — — — —

AP lumbar — — — — — — — — — —Troyanovich et al >0.70 >0.80 — — — — <2.0 <2.0 — —

Lateral cervical — — — — — — — — — —Phillips et al (1999) — >0.83 — — — <2.7† — — — —Singer et al5 — — 4.5 — — — — — — —Plaugher et al — — 2.9† 4.2† — — — — — —Cote et al — >0.90 — 9.1, 8.3‡ — — — — — —Jackson et al (Pearson r > .80) — — — — — — 1.2 1.2Harrison et alSpine >0.70 >0.80 — — 3.6, 3.2 2.2, 2.7‡ — — 2.3 2.4

Lateral thoracic — — — — — — — — — —Carman et al — — — 3.3* — — — — — —Voutsinas, MacEwen — — 2.2* — — — — — — —Jackson et al (1998) (Pearson r > .82) — — — — — — — —

Lateral lumbar — — — — — — — — — —Jackson et al (1998) (Pearson r > .73) — — — — — — — —Polly et al (1996) >0.81 >0.83 10.0 10.0 — — — — — —Voutsinas, MacEwen — — 2.1* — — — — — — —Gelb et al — — — — 3.0* 3.0* — — — —Wood et al — — — — — 1.1† — — — —Troyanovich et al >0.70 >0.80 — — — — — — 1.5 1.7Troyanovich et al >0.70 >0.80 — — — — — — 1.7 1.8

Table. Partial review of x-ray reliability studies: ICCs and standard errors of measurement for intraobserver error and interobservererror (in degrees)

ICC, Intraclass coefficient; Intra, intraobserver error; Inter, interobserver error.*Only average difference was reported (not standard error of measurement).†Standard error of measurement was reported.‡First value is for C1-C7; second value is for C2-C7.



633

“intra and intergroup correlations among orthopedic sur-geons” for 3 types of spondylolisthesis radiographic mea-surements. Similar to Tallroth et al’s194 findings for lumbarflexion/extension, the findings of Lind et al197 for cervicalflexion/extension were high examiner reliability and lowintraobserver error of measurement (<1.8 degrees) for later-al cervical segmental flexion angles. Gross et al198 (1983)and Goldberg et al199 (1988) revisited AP Cobb angle relia-bility and reported smaller errors of measurement (between1.9 and 3.2 degrees) than most studies. Similarly, DeSmet etal200 reported small interobserver errors of the differences(<1.2 degrees) for Cobb angles.

The multitude of studies just cited (a total of 35) report-ing high radiographic reliability (those with ICCs report themajority of ICCs to be in the >0.75 range) is sufficient toestablish the “reliability of radiographic analysis of spinaldisplacement” to the satisfaction of any well-informedreader.

Perhaps the high variability of SEM (ranging between 3and 10 degrees) with the 4-line Cobb methods are of con-cern. Inasmuch as the Harrison posterior tangent method hassmaller SEMs (<2 degrees), this method is suggested toHaas et al7 as well as to clinicians and other researchers forthe analysis of the sagittal spine.

However, until recently (the 1990s), most investigatorsreported only means, SDs, and SDs of differences in read-ings and rereadings (Table). Because the SEM has SD in itsformula, the low means and SDs for measurement differ-ences indicate good-to-excellent reliability. However, before1990, authors rarely provided proper statistical analyseswith Pearson r, intrarater ICC, interrater ICC, 95% CI, andSEM values. The vast majority of medical investigators havestated that the low means and SDs for differences in drawingand redrawing radiographic lines (Table) suffice for a claimof adequate reliability. After all, it is merely Euclideangeometry!

In 1999, Phillips et al201 reported high correlation coeffi-cients (0.83, 0.91, 0.89, 0.91, 0.88, 0.87) and low SEMs(2.45 degrees, 2.71 degrees, 1.69 degrees; 1.22 mm, 1.32mm, 1.48 mm) when measuring the occipital-C2 angle anddistances on neutral, flexion, and extension radiographs. Formeasuring spinal canal dimensions and cord size in a 1999review article, Rao and Fehlings202 reported that 7 studiesprovided interobserver and intraobserver reliability of radi-ographic measurements (0.82 < ICC < 0.99). In 1997, withmeans and SDs for measurement differences on AP thoracicviews, it was reported that the rib vertebral angle could bereliably measured (intraobserver mean, 4.4 degrees; interob-server mean, 3.6 degrees).203

In 1996, Omeroglu et al204 reported that “both intraobserv-er and interobserver error risks were insignificant” for use ofthe Perdriolle torsionmeter to measure vertebral axial rota-tion in scoliosis on AP radiographs.204 In 1994, Gilliam etal205 reported high ICCs for both intertester (ICC > 0.86) andintratester (ICC > 0.92) pelvic radiographic measurements.Also in 1993, Hamberg et al206 reported that “the x-ray mea-surements showed high reliability” for pelvic tilt analysis.

Recently, computer-aided spinal radiographic measure-ments have been shown to be highly reliable. For example,in 1996, Rosol et al207 reported a high Pearson correlationfor vertebral morphometry (r = 0.96) and low mean coeffi-cients of intraobserver variability (4%) and interobservervariability (2%).

We have already mentioned the recent (1998) study ofsagittal balance with normal subjects and 3 patient groupsconducted by Jackson et al.138 They reported high Pearsoncorrelation coefficients in the vast majority of their interob-server and intraobserver reliability measures (13 measuresin their Tables 8 and 9, most being greater than 0.75).138 Inaddition to the pelvic measurements, they also reported sig-nificant differences in the normal subjects and the 3 patientgroups for a multitude of lateral spine measurements. In1997, Hardacker et al208 studied lateral cervical reliabilitywith segmental Cobb angles and reported only 3 values ofinterobserver and intraoberver Pearson correlations lessthan 0.83 for 8 measurements of segmental lordosis (0.64 <r < 0.92).

In 1994, Pruijs et al209 used a Spearman correlation coef-ficient for measurements of Cobb angles on AP thoracicradiographs. They reported high coefficients (>0.98) forboth interobserver and intraobserver variation with smallSDs of differences (<3.2 degrees).

In 1996, Levine and Whittle168 measured pelvic tilt andlumbar lordosis using a television/computer system thatobtained 3-dimensional (3-D) coordinates of markers on thepelvis and spine at 20-ms intervals. ICCs for 3 readings ofpelvic tilt and lumbar lordosis were 0.78 < ICCs < 0.95. Theinvestigators reported that altering the pelvic tilt significant-ly changed the angle of lumbar lordosis.

In 1995, Saji et al167 studied 61 idiopathic scoliosis ado-lescents with 33 normal subjects for femoral neck shaftangles and asymmetry of the hips. An angle was formed bylines through the femoral shaft and neck. They also per-formed Cobb angle measurements. Intraobserver reliabilityand interobserver reliability were assessed; there were nosignificant differences between the measurements of a singleobserver or between the measurements of differentobservers. SEMs were small (intraobserver, 1.6 degrees;interobserver, 1.9 degrees). In addition, the investigatorsreported a significant difference in the obtuse femoral anglesin normal versus scoliotic subjects, the latter having muchlarger obtuse angles. In 1985, Tibrewal and Pearcy210

assessed measurement of disk heights from lateral radi-ographs. They reported a maximum error of 0.7 mm forintraobserver and interobserver measurements.

Since 1990, many chiropractic studies have included sta-tistical analyses that are extensive in comparison with thoseof previous studies. For our 6 CBP radiography reliabilitystudies, we consulted with Burt Holland, PhD, a professor inthe Department of Statistics at Temple University. With hisaid, our studies have reported complete statistical analyseswith a majority of intraobserver and interobserver ICCsgreater than 0.75 and small SEMs (<2 degrees). It is interest-ing to note that ICC > 0.60 is the set of values that Haas et


634

al7 have declared to be in the good-to-excellent range forchiropractic studies.211 This range is close to the excellentrange suggested by Shrout and Fleiss212 (poor < 0.4; 0.4 <fair to good < 0.75; excellent > 0.75).

It would be a great surprise to every mathematician,physicist, and engineer to find that radiographic line draw-ings of all types are not highly reliable. After all, it is nothing

more than Euclidean geometry, which is the basis of everyhuman-made structure in our industrial lives.

Posture Reproducibility, Reliability, and ValidityThere is in the literature a plethora of posture reliability

and reproducibility studies performed by ergonomists, med-ical doctors, chiropractors, and physical therapists. Posture

Fig 4. Four types of loads with inherent stresses.



635

has been studied with patients lying,213 sitting,214 stand-ing,215 lifting,216 working,217 walking,218 engaging in dailyroutine performance,219 and running.220 Postural stress hasbeen correlated with scoliosis,221 office work,222 work-relat-ed lifting injuries,223 driving,224 sitting,225 space flight,226

sports injuries,227 and back pain.228 Posture as a valid out-come of care is universally accepted by almost all health caresciences.229-231 Virtually every body part has been studied forits posture in normal subjects versus injured individuals;included are the postures of the head,232 shoulders,233 upperextemity,234 trunk,235 pelvis,236 lower extremity,237 and shortleg,238 as well as the whole body posture.239-251 The vastmajority of these studies report high interobserver andintraobserver reliability. In 1990, in a study of 86 Chinesesubjects, Dai and Gu252 found no significant differences inposture for males and females and no significant differencesin posture between groups of old-aged subjects and middle-aged subjects with eyes open, though they did find a differ-ence in posture between groups of old-aged subjects andmiddle-aged subjects with eyes closed. In a 1997 study of160 men and women, Raine and Twomey253 found no signif-icant gender differences for each of head and shoulder pos-ture measurements. For a review of the normal alignment ofthe lower extremities, the reader is referred to the 1996review by Riegger-Krugh and Keysor,254 who noted thatpathology of structures results from skeletal malalignment.

Adolescents’ postural faults have been established as thecause of pain syndromes in adulthood.255 Anatomical shortleg inequality has received much attention in the literature.True anatomical leg length inequality causes a recogniz-able abnormal posture. For a review, the reader is referredto the 1983 review by the American Academy of Osteo-pathy256 and to recent articles by Beaudoin et al257 andKeppler et al.258

In terms of validity, posture as a valid outcome in thehealth care sciences is well accepted. In fact, the editor ofthis Journal has made the following statement: “That pos-ture can lead to low back pain will come as a surprise to noone.”259

Last, inasmuch as Fialka-Moser et al255 reported thatadolescents’ postural faults have been established as thecause of pain syndromes in adulthood, we are bewilderedthat chiropractic state licensing boards are being influencedby the paradigm promoted by Haas et al7 and others, ascited in a recent review.8 For example, in August 1999 theNevada Board of Chiropractic Examiners told practitionersthat it was against Board ruling to take radiographs of chil-dren and that posttreatment radiographs were unwarranted.The selective information (countered in our precedingreview) generally generated and disseminated by chiroprac-tic radiologists and academicians is adversely affecting chi-ropractic clinicians’ ability to provide the best possible ser-vice to the patients who seek our care.

Clinical Utility and AppropriatenessHaas et al’s7 negation of structure (spinal alignment) as

a clinical outcome seems to be based on a few controlledclinical trials that failed to demonstrate the effectivenessof chiropractic manipulation in conditions such as asth-ma260 and nocturnal enuresis.261 These studies used spinalmanipulation as the intervention (treatment). Becausemanipulation seemed to be beneficial for headaches, neckpain, and back pain but not for other diseases or spinal dis-placement, Haas et al prefer to see chiropractic as merely atemporary treatment regimen for the relief of spinal achesand pains.

There are many flaws in this line of reasoning, and mostof these flaws are derived from a complete void in an engi-neering education. At least two topics can be applied toHaas et al’s faulty reasoning: (1) exclusive use of torsionalloads in spinal manipulation and (2) neglect of CNS biome-chanics. This whole discussion of posture and radiographicline drawing reliability/validity omits a very important clin-ical factor when any of the postural rotations and transla-tions in Figs 2 and 3 are present for long periods, especiallyflexed segments in the cervical and lumbar areas.Deformations of the CNS, which result from abnormal pos-tural loads, were recently reviewed in this Journal.262-264

Fig 5. A, Diversified technique is limited; lumbar roll is a torsional load applied to lumbar segments bytwisting pelvis relative to fixed thoracic cage. B, Cervical rotary-break is a torsional load applied to head inlateral flexed and forward flexed positions. These loads are applied to every subject; patient’s abnormalpretreatment posture is disregarded.

A B


636

Thus, of the two topics, only that of torsional loads in spinalmanipulation needs to be presented here.

Torsional LoadsLet us revisit the postural DOF in Figs 1 and 2, which are

based on the engineering concepts of rotations and transla-tions in 3 dimensions. There are 12 single movements in 6DOF for each of the head, thoracic cage, and pelvis.Through use of permutations in probability theory, it can bedetermined that there are 728 possible postures (singles,doubles, triples, . . . sextuples) of each of the head, thoraciccage, and pelvis in 3 dimensions, for a total of 7283 or385,828,352 possible upright human postures!12 This is suchan overwhelming number that it is best to restrict our discus-sion to the individual postures depicted in Figs 1 and 2.These 36 postures (12 singles each for head, thoracic cage,and pelvis) can be recategorized into the 4 types of loadstaught in junior-level engineering courses on the mechanicsof materials (Fig 4).

In mechanics of materials, engineers study the materialproperties, design, loadings, deflections, stresses, and strainsof structures.265 The y-axis rotations in Fig 1 are caused bytorsional loads, whereas the x-axis (flexion/extension) and z-axis (lateral flexion) rotations are examples of pure bending.The y-axis translations are examples of axial loads, whereasthe x-axis and z-axis translations are examples of transverse

loads. After being exposed to some anatomy and ranges ofmotion, any engineer can visualize the stresses (forces/area)and strains (measurements of deformation) in these postures.For example, in lateral flexion, the flexural stresses are com-pression on the concave fibers and tension on the convexfibers. For the paraspinal tissues, these stresses/strains aredirectly associated with Wolff’s law and Davis’ law, especial-ly for the application of these abnormal loads over long peri-ods. The previous discussion now illuminates a glaring defi-ciency in applying diversified loadings to patients’ spines.

The vast majority of diversified maneuvers are torsionalloads (Fig 5). It might seem that these loadings will have aprobability of being only 11% effective (of the 18 DOF illus-trated in Figs 1 and 2, head and thoracic torsions are only 2DOF). However, when considering the total permutations ofposture, these diversified torsional loads are 4 out of385,828,352 possible human postures, which amounts toapproximately 0% of specificity in matching the patient’sabnormal posture. Haas et al7 seemingly do not understandthe necessity of matching the patient’s individual posturebecause they do not have a realization that these (rotated andtranslated postures) are mathematical functions in linearalgebra, which is fundamental to an engineering education.

Linear algebra is the study of linear transformations.266

There are 4 important linear transformations in 3-D geometry:(1) rotations, (2) reflections, (3) projections, and (4) transla-

Fig 6. In these examples, torsional loads make subjects’ posture worse. A, Patient’s initial posture is left head lateral flexion with con-tralateral right thoracic bending (low shoulder at right). B, Patient’s head is right laterally translated with contralateral translation ofthoracic cage. Y-axis torsional loadings (seen in Fig 5) will not correct this posture and will in fact add other abnormal postural loads.

A B



637

tions. Because of a complete void in chiropractic education,clinicians and academicians are unaware that rotations, reflec-tions, and translations have unique inverses (ie, only one loadwill correct them) and that rotations, translations, and reflec-tions are the only 3-D rigid body movers (this is a theorem inmathematics). From linear algebra, one deduces that theremust be a normal (origin) from which to measure the displace-ments caused by rotations, reflections, and translations.

From the study of linear algebra, it becomes apparent thaty-axis torsional loads are inappropriate interventions in thevast majority of patients. Actually, in most cases (ie, mostpostural positions of the patient), y-axis torsional loads makethe patient’s posture worse (adding a new position not pre-sent in the initial posture). For the sake of brevity, we pro-vide only 2 examples.

Suppose the new patient has either head lateral flexionto the right and thoracic lateral flexion to the left or con-tralateral lateral translations of the head and rib cage (Fig6). A cervical rotary break, as in Fig 5, A, will causeincreased lateral flexion and the addition of head rotation,whereas a lumbar roll will not correct the thoracic lateralbending to the left but will add a y-axis rotation posture tothe patient. The torsion stresses cause deformation of themechanoreceptors in the disks, ligaments, and musclespindles (these reflexes reduce pain), but they do not alterthe initial and ongoing postural loads on the subject’sparaspinal tissues. (This simple example, like the preced-ing discussion on outside posture, neglects the configura-tions of the sagittal cervical, thoracic, and lumbar curveson the inside.)

CONCLUSIONA thorough review of normal upright posture, normal

spinal modeling, structural spinal alignment as a clinicaloutcome, and radiograph reliability has been provided. Itis up to the reader to evaluate whether it is the presentauthors or Haas et al7 who (1) have been guilty of “omit-ting of relevant studies, the misrepresentation of evidence,and the disregard of the rules of evidence”7 and/or (2) mayhave presented a “‘bits and pieces’ approach to the litera-ture, selective extracting and manipulating that whichcould be construed to be supportive of their position andignoring the rest.”267 The reader may compare the litera-ture cited by Haas et al7 and Morgan267 (a total of 49 refer-ences) with the literature cited in this review and a 1998review8 (a total of 434 references) to determine whetherpublished studies have been misrepresented and/orneglected.

A detailed response to the criticisms of Haas et al con-cerning biological plausibility, clinical sensibility, and so onhas been provided here. Finally, Haas et al and Morgan havequestioned our integrity and have become personal in theirattack on our credibility. For example, Morgan267 claims that“the Harrison et al approach to the topic of spinal displace-ment appears much less as research and much more as pro-motion.” Science requires critique of ideas, but personalattacks have no place in a scientific debate.

However, the complete void of mechanical engineeringin their reasoning has led them to a paradigm of chiropractictreatment that we do not accept. Their paradigm of treat-ment, based on torsional loads, is detrimental to thepatient’s well-being in the longitudinal sense. They seem tobe interested only in temporary “patient happiness out-comes”7 of chiropractic care, whereas we are interested inthe long-term effects of abnormal postural loads. We find itparamount to measure the patient’s structure on the outside(posture) and use radiography for the segmental alignmentson the inside (spine). The measurements gathered are usedto uniquely determine the specific interventions chosen foreach individual patient. We cannot accept the paradigm ofapplying general torsional loads to every patient.

Deed E. Harrison, DCPrivate Practice of Chiropractic

123 Second StreetElko, NV 89801

Donald D. Harrison, DC, PhD

Stephan J. Troyanovich, DC

Stacy Harmon, DC, MD

REFERENCES

1. Haldeman D, Peterson D, Chapman-Smith D. Guidelines forchiropractic quality assurance and standards of practice.Gaithersburg, Md: Aspen Publishers; 1992.

2. Harrison DD, Jackson BL, Troyanovich SJ, Robertson GA,DeGeorge D, Barker WF. The efficacy of cervical exten-sion-compression traction combined with diversifiedmanipulation and drop table adjustments in the rehabilita-tion of cervical lordosis. J Manipulative Physiol Ther1994;17:454-64.

3. Harrison DD, Troyanovich SJ, Harrison DE, Janik TJ, MurphyDJ. A normal sagittal spinal configuration: a desirable clinicaloutcome. J Manipulative Physiol Ther 1996;19:398-405.

4. Troyanovich SJ, Harrison DD. Chiropractic biophysics(CBP) technique. Chiropr Technique 1996;8:1-6.

5. Troyanovich SJ, Harrison DE, Harrison DD. Review of the sci-entific literature relevant to structural rehabilitation of the spineand posture: rationale for treatment beyond the resolution ofsymptoms. J Manipulative Physiol Ther 1998;21:37-50.

6. Troyanovich SJ, Harrison DD, Harrison DE. Low back painand the lumbar intervertebral disc: clinical considerations forthe doctor of chiropractic. J Manipulative Physiol Ther1999;22:96-104.

7. Haas M, Taylor JAM, Gillete RG. The routine use of radi-ographic spinal displacement analysis: a dissent. J Mani-pulative Physiol Ther 1999;22:254-9.

8. Harrison DE, Harrison DD, Troyanovich SJ. Reliability ofspinal displacement analysis on plane X-rays: a review ofcommonly accepted facts and fallacies with implications forchiropractic education and technique. J Manipulative PhysiolTher 1998;21:252-66.

9. Harrison DD, Janik TJ, Harrison GR, Troyanovich SJ,Harrison DE, Harrison SO. Chiropractic biophysics tech-nique: a linear algebra approach to posture in chiropractic. JManipulative Physiol Ther 1996;19:525-35.

10. Harrison DD. CBP technique: the physics of spinal cor-rection. National Library of Medicine #WE 725 4318C,1982-97.

11. Harrison DD. Spinal biomechanics: a chiropractic perspective.National Library of Medicine #WE 725 4318C, 1982-97.


638

12. Harrison DD. Abnormal postural permutations calculated asrotations and translations from an ideal normal upright staticspine. In: Sweere JJ, editor. Chiropractic family practice.Gaithersburg, Md: Aspen Publishers; 1992. p 6-1:1-22.

13. Janik TJ, Harrison DD, Cailliet R, Troyanovich SJ, HarrisonDE. Can the sagittal lumbar curvature be closely approximat-ed by an ellipse? J Orthop Res 1998;16:766-70.

14. Harrison DD, Janik TJ, Troyanovich SJ, Holland B.Comparisons of lordotic cervical spine curvatures to a theo-retical ideal model of the static sagittal cervical spine. Spine1996;21:667-75.

15. Harrison DD, Janik TJ, Troyanovich SJ, Harrison DE,Colloca CJ. Evaluations of the assumptions used to derive anideal normal cervical spine model. J Manipulative PhysiolTher 1997;20:246-56.

16. Harrison DD, Janik TJ. Clinical validation of an ideal normalstatic cervical spine model. In: Witten M, editor.Computational medicine, public health, and biotechnology, 2.Austin, Tex: World Scientific Publishing; 1995. p 1047-55.

17. Janik TJ, Harrison DD. Prediction of 2-D static normal posi-tion of the cervical spine from mathematical modeling. In:Witten M, editor. Computational medicine, public health, andbiotechnology, 2. Austin, Tex: World Scientific Publishing;1995. p 1036-46.

18. Troyanovich SJ, Cailliet R, Janik TJ, Harrison DD, HarrisonDE. Radiographic mensuration characteristics of the sagittallumbar spine from a normal population with a method tosynthesize prior studies of lordosis. J Spinal Disord 1997;10:380-6.

19. Harrison DD, Cailliet R, Janik TJ, Troyanovich SJ, HarrisonDE, Holland B. Elliptical modeling of the sagittal lumbar lor-dosis and segmental rotation angles as a method to discrimi-nate between normal and low back pain subjects. J SpinalDisord 1998;11:430-9.

20. Cowin S. Bone mechanics. Boca Raton, Fla: CRC Press;1989. p 37.

21. White AA, Panjabi MM. Clinical biomechanics. Phila-delphia: Lippincott; 1978.

22. Harrison DE, Harrison DD, Troyanovich SJ. Three-dimen-sional spinal coupling mechanics, I: a review of the literature.J Manipulative Physiol Ther 1998;21:101-13.

23. Harrison DE, Harrison DD, Troyanovich SJ. Three-dimen-sional spinal coupling mechanics, II: implications for chiro-practic theories and practice. J Manipulative Physiol Ther1998;21:177-86.

24. Carlsoo S. The static muscle load in different work positions:an electromyographic study. Ergonomics 1961;4:193-211.

25. Klausen K. The form and function of the loaded human spine.Acta Physiol Scand 1965;65:176-90.

26. Nachemson A, Elfstrom G. Intravital dynamic pressure mea-surements in lumbar discs: a study of common movements,maneuvers and exercises. Scand J Rehabil Med 1970;1(Suppl):1-40.

27. Andersson BJG, Ortengren R, Nachemson A, Elfstrom G.Lumbar disc pressure and myoelectric back muscle activityduring sitting, I: studies on an experimental chair. Scand JRehabil Med 1974;6:104-14.

28. Basmajian JV, Bentzon JW. Electromyographic study of cer-tain muscles of the leg and foot in the standing position. SurgGynecol Obstet 1954;98:662-6.

29. Basmajian JV. Electromyography of iliopsoas. Anat Rec1958;130:267.

30. Floyd WF, Silver PHS. The function of the erector spinaemuscles in certain movements and postures in man. J Physiol1955;129:184-203.

31. Joseph J, Nightingale A. Electromyography of muscles ofposture: leg muscles in males. J Physiol 1952;117:484-91.

32. Joseph J, Nightingale A. Electromyography of muscles ofposture: thigh muscles in males. J Physiol 1954;126:81-5.

33. Joseph J, Nightingale A, Williams PL. A detailed study of theelectric potentials recorded over some postural muscles whilerelaxed and standing. J Physiol 1955;127:617-25.

34. Joseph J, Nightingale A. Electromyography of muscles ofposture: leg and thigh muscles in women, including theeffects of high heels. J Physiol 1956;132:465-8.

35. Harrison DE, Cailliet R, Harrison DD, Janik TJ, TroyanovichSJ, Coleman RR. Lumbar coupling during lateral translationsof the thoracic cage relative to a fixed pelvis. Clin Biomech1999;14:704-9.

36. Harrison DE, Cailliet R, Harrison DD, Janik TJ, TroyanovichSJ. Cervical coupling during lateral translations of the head.Clin Biomech 2000;15:436-40.

37. Williams PL, Warwick R. Grays anatomy. 36th ed.Philadelphia: WB Saunders; 1980.

38. Farfan HP. Mech disorders of the low back. Philadelphia: Lea& Febiger; 1973. p 34-5.

39. Woodhull AM, Maltrud K, Mello BL. Alignment of thehuman body in standing. Eur J Appl Physiol 1985;54:109-15.

40. Wells KF, Luttgens K. Kinesiology: scientific basis of humanmotion. 6th ed. Philadelphia: WB Saunders; 1976.

41. Hellebrandt FA, Tepper RH, Braun CL, Elliott MC. The loca-tion of the cardinal anatomical orientation planes passingthrough the center of weight in young adult women. Am JPhysiol 1938;121:465-70.

42. Hellebrandt FA, Hirt S, Fries EC. Centre of gravity of thehuman body. Arch Phys Ther 1944;25:465-70.

43. May J. The placement of the gravity line on the human bodyin the anterior-posterior plane and its relationship to postureby roentgenoscopic study [unpublished thesis]. Ames, Iowa:State University of Iowa; 1955.

44. Smidt GL, Day JW, Gerleman DG. Iowa anatomical positionsystem: a method of assessing posture. Eur J Appl Physiol1984;52:407-13.

45. Kapandji AI. The physiology of the joints. Vol 3. New York:Churchill Livingstone; 1974. p 15.

46. Kendall HO, Kendall FP, Boynton DA. Posture and pain.Baltimore: Williams & Wilkins; 1952.

47. Kuchera M. Gravitational stress, musculoligamentous strain,and postural alignment. Spine: State of the Art Reviews1995;9:463-89.

48. Kiefer A, Shirazi-Adl A, Parnianpour M. Synergy of thehuman spine in neutral postures. Eur Spine J 1998;7:471-9.

49. Hanten WP, Lucio RM, Russell JL, Brunt D. Assessment oftotal head excursion and resting head posture. Arch Phys MedRehabil 1991;72:877-80.

50. Less M, Eihelberg W. Force changes in neck vertebrae andmuscles. In: Komi P, editor. Biomechanics. Vol VA. Baltimore:University Park Press; 1976. p 530-36.

51. Ferguson D. Posture aching and body build in telephonists. JHum Ergol 1976;5:183-86.

52. Biraune W, Fischer O. On the center of gravity of the humanbody. New York: Springer-Verlag; 1985.

53. Vital JM, Senegas J. Anatomical bases of the study of theconstraints to which the cervical spine is subject in the sagit-tal plane: a study of the center of gravity of the head. SurgRadiol Anat 1986;8:169-73.

54. McKenzie RA. The cervical and thoracic spine: mechanicaldiagnosis and therapy. Waikanae, New Zealand: SpinalPublications, Ltd; 1990.

55. Garrett TR, Youdas JW, Madson TJ. Reliability of measuringforward head posture in a clinical setting. J Orthop SportsPhys Ther 1993;17:155-60.

56. Lundstrom F, Lundstrom A. Natural head position as a basisfor cephalometric analysis. Am J Orthod Dentofacial Orthop1992;101:244-7.



639

57. Haughie LJ. Fiebert IM, Roach KE. Relationship of forwardhead posture and cervical backward bending to neck pain. JManual Manip Ther 1995;3:91-7.

58. Lafferty-Braun B, Amundson LR. Quantitative assessment ofhead and shoulder posture. Arch Phys Med Rehabil1989;70:322-9.

59. Ayub E, Glasheen-Wray M, Kraus S. Head posture: a casestudy of the effects of the rest position of the mandible. JOrthop Sports Phys Ther 1984;8:179-83.

60. Darnell MW. A proposed chronology of events for forwardhead posture. J Craniomandibular Pract 1983;1:49-54.

61. Saunders HD, Saunders R. Evaluation, treatment and preven-tion of musculoskeletal disorders. In: Saunders HD, SaundersR. Spine. 3rd ed. Vol 1. Minneapolis, Minn: EducationalOpportunities; 1993.

62. Beck A, Killus J. Normal posture of spine determined bymathematical and statistical methods. Aerospace Med 1973;44:1277-81.

63. Beck A, Killus J. Analyse par computer de la statique durachis [Computer analysis of spinal measurements]. J RadiolElectrol Med Nucl 1975;56(suppl 2):402-3.

64. Staffel F. Die menschlichen haltungstypen und ihre beziehun-gen zu den ruckratsverkrummungen. Wiebaden; 1889.

65. Goff CW. Orthograms of posture. J Bone Joint Surg 1952;34A:115-22.

66. Leger W. Die wirbelsaulenhaltung und ihre krankhaftenstrorungen. WS i. Forschung und Praxis 1968;40:25-34.

67. Haglund P. Die prinzipien der orthopadie. Jena, Germany:Fischer; 1923.

68. Osgood RB. Body mechanics and posture. JAMA 1931;96:2032-5.

69. Wiles P, Lond MS. Postural deformities of the antero-posteri-or curves of the spine. Lancet 1937;1:911-9.

70. Gore DR, Sepic SB, Gardner GM. Roentgenographic findingsof the cervical spine in asymptomatic people. Spine 1986;11:521-4.

71. Mamairas C, Barnes MR, Allen MJ. “Whiplash injuries” ofthe neck: a retrospective study. Injury 1988;19:393-6.

72. Pedersen PL. A prospective pilot study of the shape of cervi-cal hypolordosis. Eur J Chiropr 1990;38:148-63.

73. Borden AGB, Rechtman AM, Gershon-Cohen J. The normalcervical lordosis. Radiology 1960;74:806-10.

74. Marshall DL, Tuchin PJ. Correlation of cervical lordosis mea-surement with incidence of motor vehicle accidents. J AustrChiropr Osteopathy 1996;5:79-85.

75. Gay RE. The curve of the cervical spine: variations and sig-nificance. J Manipulative Physiol Ther 1993;16:591-4.

76. Harrison DD, Harrison DLJ. Pathological stress formationson the anterior vertebral body in the cervicals. In: Suh CH,editor. Proceedings of the 14th Annual Biomechanics Con-ference on the Spine; 1982 Nov 5-6; Oakland, Calif. Mechan-ical Engineering Department, University of Colorado; 1983.p 31-50.

77. Harrison DE, Harrison DD, Troyanovich SJ, Caillet R, JanikTJ, Holland B. Cobb method or Harrison posterior tangentmethod: which to choose of lateral cervical radiographicanalysis. Spine 2000;25:2072-8.

78. Cote P, Cassidy JD, Yong-Hing K, Sibley J, Loewy J.Apophysial joint degeneration, disc degeneration, and sagittalcurve of the cerivcal spine. Spine 1997;22:859-64.

79. Braaf MM, Rosner S. Trauma of the cervical spine as a causeof chronic headache. J Trauma 1975;15:441-6.

80. Vernon H, Steiman I, Hagino C. Cervicogenic dysfunction inmuscle contraction headache and migraine: a descriptivestudy. J Manipulative Physiol Ther 1992;15:418-29.

81. Nagasawa A, Sakakibara T, Takahashi A. Roentgenographicfindings of the cervical spine in tension-type headache.Headache 1993;33:90-5.

82. Goto S, Kita T. Long-term follow-up evaluation of surgeryfor ossification of the posterior longitudinal ligament. Spine1995;20:2247-56.

83. Yamazaki A, Homma T, Uchiyama S, Katsumi Y, OkumuraH. Morphologic limitations of posterior decompression bymidsagittal splitting method for myelopathy caused by ossifi-cation of the posterior longitudinal ligament in the cervicalspine. Spine 1999;24:32-4.

84. Johnston EC, Birch JG, Daniels JL. Cervical kyphosis inpatients who have Larsen syndrome. J Bone Joint Surg1996;78A:538-45.

85. Baba H, Uchida K, Maezawa Y, Furusawa N, Azuchi M,Imura X. Lordotic alignment and posterior migration of thespinal cord following en bloc open-door laminoplasty forcervical myelopathy: a magnetic resonance imaging study. JNeurol 1996;243:626-32.

86. Naderi S, Ozgen S, Pamir MN, Ozek MM, Erzen C. Cervicalspondylotic myelopathy related to postoperative spinal defor-mity: a case report. Am J Phys Med Rehabil 1997;76:73-5.

87. Stein J. Failure of magnetic resonance imaging to reveal thecause of a progressive cervical myelopathy: surgical resultsand factors affecting prognosis. Neurosurgery 1998;43:43-9.

88. Swank ML, Sutterlin CE, Bossons CR, Dials BE. Rigid inter-nal fixation with lateral mass plates in multilevel anterior andposterior reconstruction of the cervical spine. Spine1997;22:274-82.

89. Batzdorf U, Flannigan BD. Surgical decompressive proce-dures for cervical spondylotic myelopathy: a study usingmagnetic resonance imaging. Spine 1991;16:123-7.

90. Aboulker J, Metzger I, David M. Les myelopathies cervicalesd’origine rachidienne. Neurochirurgie 1965;11:87-198.

91. Adams C, Logue V. Studies in cervical spondylotic myelopa-thy: functional effects of operations for cervical spondyloticmyelopathy. Brain 1971;94:587-94.

92. Butler JC, Whitecloud TD. Postlaminectomy kyphosis: caus-es and surgical management. Orthop Clin North Am1992;23:505-11.

93. Epstien JA, Janin Y, Carras R, Lavine LS. A comparativestudy of the treatment of cervical spondylotic myeloradicu-lopathy: experience with 50 cases treated by means of exten-sive laminectomy, foraminotomy, and excision of osteo-phytes during the past 10 years. Acta Neurochir (Wien)1982;61:89-104.

94. Lowery G. Three-dimensional screw divergence and sa-gittal balance: a personal philosophy relative to cervi-cal biomechanics. Spine: State of the Art Reviews1996;10:343-56.

95. Katsuura A, Hukuda S, Imanaka T, Miyamoto K, KanemotoM. Anterior cervical plate used in degenerative disease canmaintain cervical lordosis. J Spinal Disord 1996;9:470-6.

96. Kawakami M, Tamaki T, Yoshida M, Hayashi N, Ando M,Yamada H. Axial symptoms and cervical alignments aftercervical anterior spinal fusion for patients with cervicalmyelopathy. J Spinal Disord 1999;12:50-6.

97. Jones AMM, Stringer EA, Wong DA. Plated cervical fusionsyield better outcomes. Orthop Trans 1988-1999;22:524.

98. Hohl M. Soft-tissue injuries of the neck in automobile acci-dents. J Bone Joint Surg Am 1974;56A:1675-82.

99. Norris SH, Watt I. The prognosis of neck injuries resultingfrom rear-end vehicle collisions. J Bone Joint Surg Br1983;65B:608-11.

100. Ettlin TM, Kischka U, Reichmann S, Radii EW, Heim S,Wengen D, et al. Cerebral symptoms after whiplash injury ofthe neck: a prospective clinical and neuropsychological studyof whiplash injury. J Neurol Neurosurg Psychiatry 1992;55:943-8.

101. Matsunaga S, Sakou T, Sunahara N, Oonishi T, Maeda S,Nakanisi K. Biomechanical analysis of buckling alignment


640

of the cervical spine: predictive value for subaxial subluxa-tion after occipitocervical fusion. Spine 1997;22:765-71.

102. Matsunaga S, Sakou T, Taketomi E, Nakanisi K. Effects ofstrain distribution in the intervertebral discs on the progres-sion of ossification of the posterior longitudinal ligaments.Spine 1996;21:1849.

103. Matsunaga S, Sakou T, Nakanisi K. Analysis of the cervicalspine alignment following laminoplasty and laminectomy.Spinal Cord 1999;37:20-4.

104. White AA, Panjabi MM. Clinical biomechanics of the spine.2nd ed. Philadelphia: JB Lippincott; 1990.

105. Toyama Y, Matsumoto M, Chiba K, Asazuma T, Suzuki N,Fujimura Y, et al. Realignment of postoperative cervicalkyphosis in children by vertebral remodeling. Spine1994;19:2565-70.

106. Olszewski J, Kochanowski J, Zalewski P, Chmielewski H.The effect of neck rotation on auditory evoked brainstempotentials in patients with degenerative cervical spinechanges. Neurol Neurochir Pol 1993;27:23-9.

107. Frymoyer JW, Ducker TB, Hadler NM, Kostuik JP, WeinsteinJN, Whitecloud TS. The adult spine: principles and practice.2nd ed. Philadelphia: Lippincott-Raven; 1997. p 1406-9.

108. Bagnall KM, Harris PF, Jones PRM. A radiographic study ofthe human fetal spine. J Anat 1977;124:791-802.

109. Refshauge KM, Goodsell M, Lee M. The relationshipbetween surface contour and vertebral body measures ofupper spine curvature. Spine 1994;19:2180-5.

110. Johnson GM. The correlation between surface measurementof the head and neck posture and the anatomic position of theupper cervical vertebrae. Spine 1998;23:921-7.

111. D’Osualdo F, Schierano S, Iannis M. Validation of clinicalmeasurement of kyphosis with a simple instrument, theArcometer. Spine 1997;22:408-13.

112. Willner S, Johnson B. Thoracic kyphosis and lumbar lordosisduring the growth period. Acta Paediatr Scand 1983;72:873-8.

113. Carr AJ, Jefferson RJ, Turner-Smith AR, Beavis A. An analy-sis of normal back shape measured by ISIS scanning. Spine1991;16:656-9.

114. Voutsinas SA, MacEwen GD. Sagittal profiles of the spine.Clin Orthop 1986;210:235-42.

115. Bradford DS, Moe JH, Montalvo FJ, Winter RB. Scheuer-man’s kyophosis and roundback deformity: results of Mil-waukee brace treatment. J Bone Joint Surg Am 1974;56A:740-58.

116. Moe JH, Winter RB, Bradford DS, Lonstein JE. Kyphosis-lordosis: general principles. In: Moe JH, Winter RB, BradfordDS, Lonstein JE, editors. Scoliosis and other spinal deformi-ties. Philadelphia: WB Saunders; 1978. p 325-330.

117. Propst-Proctor SL, Bleck EE. Radiographic determination oflordosis and kyphosis in normal and scoliotic children. JPediatr Orthop 1983;3:344-6.

118. Roaf R. Vertebral growth and its mechanical control. J BoneJoint Surg Br 1960;42B:40-59.

119. Stagnara P, De Mauroy JC, Dran G, Fonon GP, Costanzo G,Dimnet J, et al. Reciprocal angulation of vertebral bodies in asagittal plane: approach to references for the evaluation ofkyphosis and lordosis. Spine 1982;7:335-42.

120. Singer KP, Edmondston SJ, Day RE, Breidahl WH. Computer-assisted curvature assessment and Cobb angle determinationof the thoracic kyphosis: an in vivo and in vitro comparison.Spine 1994;19:1381-4.

121. Milne JS, Williamsson J. A longitudinal study of kyphosis inolder people. Age Ageing 1983;12:225-33.

122. Korovessis PG, Stamatakis MV, Baikousis AG. Reciprocalangulation of vertebral bodies in the sagittal plane in anasymptomatic Greek population. Spine 1998;23:700-5.

123. Bernhardt M, Bridwell KH. Segmental analysis of the sagittal

plane alignment of the normal thoracic and lumbar spines andthoracolumbar junction. Spine 1989;14:717-21.

124. Jackson RP, McManus AC. Radiographic analysis of sagittalplane alignment and balance in standing volunteers andpatients with low back pain matched for age, sex, and size.Spine 1994;19:1611-8.

125. Vedantam R, Lenke LG, Keeney JA, Bridwell KH. Com-parison of standing sagittal spinal alignment in asymptomaticadolescents and adults. Spine 1998;23:211-5.

126. Fon GT, Pitt MJ, Thies AC Jr. Thoracic kyphosis: range innormal subjects. AJR Am J Roentgenol 1980;134:979-83.

127. Cutler WB, Friedmann E, Genovese-Stone E. Prevalence ofkyphosis in a healthy sample of pre- and postmenopausalwomen. Am J Phys Med Rehabil 1993;72:219-25.

128. Kolessar DJ, Stollsteimer GT, Betz RR. The value of the mea-surement from T5 to T12 as a screening tool in detectingabnormal kyphosis. J Spinal Disord 1996;9:220-3.

129. Gelb DE, Lenke LG, Bridwell KH, Blanke KB, McEneryKW. An analysis of sagittal spinal alignment in 100 asymp-tomatic middle and older aged volunteers. Spine 1995;20:1351-8.

130. Wambolt A, Spencer DL. A segmental analysis of the distri-bution of the lumbar lordosis in the normal spine. OrthopTrans 1987;11:92-3.

131. Wood KB, Kos P, Schendel M, Persson K. Effect of patientposition on the sagittal-plane profile of the thoracolumbarspine. J Spinal Disord 1996;9:165-9.

132. Vendantam R, Lenke LG, Keeney JA, Bridwell KH. Com-parison of standing sagittal spinal alignment in asymptomaticadolescents and adults. Spine 1998;23:211-5.

133. Chen YL. Geometric measurements of the lumbar spine inChinese men during trunk flexion. Spine 1999;24:666-9.

134. Mosner EA, Bryan JM, Stull MA, Shippee R. A comparisonof actual and apparent lumbar lordosis in black and whiteadult females. Spine 1989;14:310-4.

135. Fernand R, Fox DE. Evaluation of lumbar lordosis: a prospec-tive and retropspective study. Spine 1985;10:799-803.

136. Korovessis P, Stamatakis M, Baikousis A. Segmental roent-genographic analysis of vertebral inclination on sagittal planein asymptomatic versus chronic low back pain patients. JSpinal Disord 1999;12:131-7.

137. Chen MW, Yang SW, Lee MC. Changes in lumbar disc anglesof Chinese subjects from upright to flexion. Spine 1994;19:1490-4.

138. Jackson RP, Peterson MD, McManus AC, Hales C. Com-pensatory spinopelvic balance over the hip axis and betterreliability in measuring lordosis to the pelvic radius on stand-ing lateral radiographs of adult volunteers and patients. Spine1998;23:1750-67.

139. Berlemann U, Jeszenszky DJ, Buhler DW, Harms J. The roleof lumbar lordosis, vertebral end-plate inclination, disc height,and facet orientation in degenerative spondylolisthesis. JSpinal Disord 1999;12:68-73.

140. Bull P, Hayek R. The effects of spondylolisthesis on the lum-bar spine. Presented at the 5th World Federation for Chiro-practic Research. Auckland, New Zealand; 1999 May; p 269-270.

141. Klein JR, Schwab FJ, Hoffman BD, Schechter C, FarcyJPC. Pelvic retroversion: a compensatory mechanism insagittal spinal deformity. Presented at the 26th AnnualISSLS Conference; Honolulu, Hawaii; 1999 Jun 21-25. p180B.

142. Adams MA, Mannion AF, Dolan P. Personal risk factors forfirst-time low back pain. Presented at the 26th Annual ISSLSConference; Honolulu, Hawaii; 1999 Jun 21-25. p 82.

143. Itoi E. Roentgenographic analysis of posture in spinal osteo-porotics. Spine 1991;16:750-6.

144. Takemitsu Y, Sumita N, Kida H. Clinical and roentgenologic



641

study of the malposture “flat back.” Rinsho Seikei Geka1970;5:568-78.

145. Louis RP, Louis C, Aswad R. L5 anterior osteotomy forpainful hyperlordosis. Prsented at the 26th Annual ISSLSConference; Honolulu, Hawaii; 1999 Jun 21-25. p 212B.

146. Ahn UM, Buchowski JM, Sieber AN, Lee JH, Hirakawa K,Cohen D, et al. Spinal osteotomy. Presented at the 26thAnnual ISSLS Conference; Honolulu, Hawaii; 1999 Jun 21-25. p 203B.

147. La Grone MO. Loss of lumbar lordosis: a complication ofspinal fusion for scoliosis. Orthop Clin North Am 1988;19:383-93.

148. Peterson MD, Nelson LM, McManus AC, Jackson RP. Theeffect of operative position on lumbar lordosis: a radiograph-ic study of patients under anesthesia in the prone and 90-90positions. Spine 1995;20:1419-24.

149. Marsicano JG, Lenke LG, Bridwell, Chapman M, Gupta P,Weston J. The lordotic effect of the OSI frame on operativeadolescent idiopathic scoliosis patients. Spine 1998;23:1341-8.

150. Guanciale AF, Dinsay JM, Watkins RG. Lumbar lordosis inspinal fusion: a comparison of intraoperative results ofpatient positioning on two different operative table frametypes. Spine 1996;21:964-9.

151. Tribus CB, Belanger TA, Zdeblick TA. The effect of opera-tive position and short segment fusion on maintenance ofsagittal alignment of the lumbar spine. Spine 1999;24:58-61.

152. Schlegel JD, Smith JA, Schleusener RL. Lumbar motion seg-ment pathology adjacent to thoracolumbar, lumbar, and lum-bosacral fusions. Spine 1996;21:970-81.

153. Matsunaga S, Sakou T, Nagayama T, Nakanishi K. A newbiomechanical analysis of the degenerative lumbar spine. In:Takahashi HE, editor.Spinal disorders in growth and aging.Tokyo: Springer-Verlag; 1995. p 175-82.

154. Matsunaga S, Sakou T, Taketomi E, Ijiri K. Comparison ofoperative results of lumbar disc herniation in manual laborersand athletes. Spine 1993;18:2222-6.

155. Izumi Y, Kumano K, Shimizu H, Uchida T, Hirabayashi S.Analysis of sagittal lumbar alignment before and after poste-rior spinal instrumentation: risk factors for adjacent unfusedsegment. Presented at the Scoliosis Research Society meet-ing; St Louis, Mo; 1997 Sep 25-2.

156. Fukuyama S, Nakamura T, Ikeda T, Takagi K. The effect ofmechanical stress on hypertrophy of the lumbar ligamentumflavum. J Spinal Disord 1995;8:126-30.

157. Vachalathiti R. Effects of age, gender and body mass index onspinal curvature in standing. Presented at the 26th AnnualISSLS Conference; Honolulu, Hawaii; 1999 Jun 21-25. p 219B.

158. Stokes IA, Bevins TM, Lunn RA. Back surface curvatureand measurement of lumbar spinal motion. Spine 1987;12:355-61.

159. Jeffries BF, Tarlton M, DeSmet A, Dwyer SJ, Brower AC.Computerized measurement and analysis of scoliosis. Ra-diology 1980;134:381-5.

160. Stokes IAF, Bigalow LC, Moreland MS. Three-dimensionalspinal curvature in idiopathic scoliosis. J Orthop Res 1987;5:102-13.

161. Singer KP, Jones TJ, Breidahl PD. A comparison of radi-ographic and computer-assisted measurements of thoracicand thoracolumbar sagittal curvature. Skeletal Radiol 1990;19:21-6.

162. Yoganandan N, Kumaresan S, Voo L, Pintar F. Spine update:finite element applications in human cervical spine modeling.Spine 1996;21:1824-34.

163. Yoganandan N, Myklebust JB, Ray G, Sances A Jr. Mathe-matical and finite element analysis of spine injuries. Crit RevBiomed Eng 1987;15:29-93.

164. Gilbertson LG, Goel VK, Kong WZ, Clausen JD. Finite ele-ment methods in spine biomechanics research. Crit RevBiomed Eng 1995;23:411-73.

165. Plaugher G, Hendricks AH, Doble RW, Bachman, TR, AraghiHJ, Hoffart VM. The reliability of patient positioning forevaluating static radiographic parameters of the humanpelvis. J Manipulative Physiol Ther 1993;16:517-22.

166. Troyanovich SJ, Harrison DE, Janik TJ, Harrison DD. A fur-ther analysis of the reliability of the posterior tangent laterallumbar radiographic mensuration procedure: concurrentvalidity of computer aided x-ray digitization. J ManipulativePhysiol Ther 1998;21:460-7.

167. Saji MJ, Upadlhyay SS, Leong JC. Increased femoral neck-shaft angles in adolescent idiopathic scoliois. Spine 1995;20:303-11.

168. Levine D, Whittle MW. The effects of pelvic movement onlumbar lordosis in the standing position. J Orthop SportsPhys Ther 1996;24:130-5.

169. Jackson BL, Harrison DD, Robertson GA, Barker WF.Chiropractic biophysics lateral cervical film analysis reliabil-ity. J Manipulative Physiol Ther 1993;16:384-91.

170. Troyanovich S, Robertson GA, Harrison DD, Holland B.Intra- and interexaminer reliability of the chiropractic bio-physics lateral lumbar radiographic mensuration procedure. JManipulative Physiol Ther 1995;18:519-24.

171. Troyanovich SJ, Harrison SO, Harrison DD, Harrison DE,Payne M, Janik TJ, et al. Chiropractic biophysics digitizedradiographic mensuration analysis of the anteroposteriorlumbar view: a reliability study. J Manipulative Physiol Ther1999;22:309-15.

172. Troyanovich SJ, Harrison DE, Harrison DD, Harrison SO,Janik TJ, Holland B. Chiropractic biophysics digitized radi-ographic mensuration analysis of the anteroposterior cervi-cothoracic view: a reliability study. J Manipulative PhysiolTher. In press 2000.

173. Jackson BL, Barker WF, Bentz J, Gambale AG. Inter- andintra-examiner reliability of the upper cervical X-ray markingsystem: a second look. J Manipulative Physiol Ther 1985;10:157-63.

174. Rochester RP. Inter- and Intra-examiner reliability of theupper cervical x-ray marking system: a third and expandedlook. Chiropr Res J 1994;3:23-7.

175. Plaugher G, Cremata EE, Phillips RB. A retrospective con-secutive case analysis of pre-treatment and comparative staticradiographic parameters following chiropractic adjustments.J Manipulative Physiol Ther 1990;13:498-506.

176. Plaugher G, Hendricks AH. The inter and intraexaminer relia-bility of the Gonstead pelvic marking system. J ManipulativePhysiol Ther 1991;14:503-8.

177. Oda M, Rauh S, Gregory PB, Silverman FN, Black EE. Thesignificance of roentgenographic measurement in scoliosis. JPediatr Orthop 1982;2:378-82.

178. Sevastikoglou JA, Bergquist E. Evaluation of the reliability ofradiological methods for registration of scoliosis. ActaOrthop Scand 1969;40:608-13.

179. Wilson MS, Stockwell J, Leedy MG. Measurement of scolio-sis by orthopedic surgeons and radiologists. Aviat SpaceEnviron Med 1983;54:69-71.

180. Cote P, Cassidy JD, Yong-Hing K, Sibley J, Loewy J.Apophysial joint degeneration, disc degeneration, and sagit-tal curve of the cervical spine. Spine 1997;22:859-64.

181. Polly DW, Kilkelly FX, McHale KA, Asplund LM, MulliganM, Chang AS. Measurement of lumbar lordosis: evaluation ofintraobserver, interobserver, and technique variability. Spine1996;21:1530-6.

182. George K, Rippstein J. A compararative study of the two pop-ular methods of measuring scoliotic deformity of the spine. JBone Joint Surg Am 1961:43;809-18.


642

183. Kittleson AC, Lim LW. Measurement of scliosis. Am JRoentgenol Radium Ther Nucl Med 1970;108:775-7.

184. Moe J, Gustilo RB. Treatment of scoliosis: results in 196patients treated by cast correction and fusion. J Bone JointSurg 1964;46:293-312.

185. Neugebauer H. Cobb or Ferguson? An analysis of the twomost commonly used methods of measurement in scoliosis. ZOrthop 1972;110:342-56.

186. James JIP. Scoliosis. New York: Churchill-Livingston; 1976. 187. Shea KG, Stevens PM, Nelson M, Smith JT, Masters KS,

Yandow S. A comparison of manual versus computer-assistedradiographic measurement: intraobserver measurement vari-ability for Cobb angles. Spine 1998;23:551-5.

188. Carman DL, Browne RH, Birch JG. Measurement of scoliosisand kyphosis radiographs: intraobserver and interobservervariation. J Bone Joint Surg Am 1990;72:328-33.

189. Morrissy RT, Goldsmith GS, Hall EC, Kehl D, Cowie H.Measurement of the Cobb angle on radiographs of patientswho have scoliosis. J Bone Joint Surg Am 1990;72:320-7.

190. Beekman CE, Hall V. Variability of scoliosis measurementfrom spinal roentgenograms. Phys Ther 1979;59:764-5.

191. Neugebauer H. The different methods of measuring the curveof a scoliotic spine. In: Drerup B, Fobin W, Hierholzer E.Proceedings of the 2nd International Symposium on MoireFringe Topography and Spinal Deformity. Stuttgart: GustavFischer; 1983. p 17.

192. Saraste H, Brostrom LA, Aparisis T, Axdorph G. Radio-graphic measurement of the lumbar spine: a clinical andexperimental study in man. Spine 1985;10:236-41.

193. Shaffer WO, Spratt KF, Weinstein J, Lehmann TR, Goel V.The consistency and accuracy of roentgenograms for measur-ing sagittal translation in the lumbar vertebral motion seg-ment: an experimental model. Spine 1990;15:741-50.

194. Tallroth K, Ylikoski M, Landtman M, Santavirta S. Relia-bility of radiological measurements of spondylolisthesis andextension-flexion radiographs of the lumbar spine. Eur JRadiol 1994;18:227-31.

195. Fann AV, Lee R, Verbois GM. The reliability of postural x-rays in measuring pelvic obliquity. Arch Phys Med Rehabil1999;80:458-61.

196. Capasso G, Maffulli N, Testa V. Inter- and intrarater reliabili-ty of radiographic measurements of spondylolisthesis. ActaOrthop Belg 1992;58:188-92.

197. Lind B, Sihlbom H, Nordwall A, Malchau H. Normal rangeof the cevical spine. Arch Phys Med Rehabil 1989;70:692-5.

198. Gross C, Gross M, Kuschner S. Error analysis of scoliosiscurvature measurement. Bull Hosp Joint Dis Orthop Inst1983;43:171-7.

199. Goldberg MS, Poitras B, Mayo NE, Labelle H, Bourassa R,Cloutier R. Observer variation in assessing spinal curvatureand skeletal development in adolescent idiopathic scoliosis.Spine 1988;13:1371-7.

200. DeSmet AA, Goin JE, Asher MA, Scheuch HG. A clinicalstudy of the differences between the scoliotic angles mea-sured on posteroanterior and anteroposterior radiographs. JBone Joint Surg Am 1982;64A:489-93.

201. Phillips FM, Phillips CS, Wetzel FT, Gelinas C. Occipi-tocervical neutral position: possible surgical implications.Spine 1999;24:775-8.

202. Rao SC, Fehlings MG. The optimal method for assessingspinal canal compromise and cord compression in patientswith cervical spinal cord injury, I: an evidenced-basedanalysis of the published literature. Spine. 1999;24:598-604.

203. McAlindon RJ, Kruse RW. Measurement of rib vertebralangle difference: intraobserver error and interobserver varia-tion. Spine 1997;22:198-9.

204. Omeroglu H, Ozekin O, Bicimoglu A. Measurement of verte-

bral rotation in idiopathic scoliosis using the Perdriolle tor-sionmeter: a clinical study on intraobserver and interobservererror. Eur Spine J 1996;5:167-71.

205. Gilliam J, Brunt D, MacMillan M, Kinard RE, MontgomeryWJ. Relationship of the pelvic angle to the sacral angle: mea-surement of clinical reliability and validity. J Orthop SportsPhys Ther 1994;20:193-9.

206. Hamberg J, Bjorklund M, Nordgren B, Sahlstedt B.Stretchability of the rectus femoris muscle: investigation ofvalidity and intratester reliability of two methods including x-ray analysis of pelvic tilt. Arch Phys Med Rehabil 1993;74:263-70.

207. Rosol MS, Cohen GL, Halpern EF, Chew FS, KattapuramSV, Palmer WE, et al. Vertebral morphometry derived fromdigital images. AJR Am J Roentgenol 1996;167:1545-9.

208. Hardacker JW, Shuford RF, Capicotto PN, Pryor PW. Radio-graphic standing cervical segmental alignment in adultvolunteers without neck symptoms. Spine 1997;22:1472-80.

209. Pruijs JE, Hageman MA, Keessen W, van der Meer R, vanWieringen JC. Variation in Cobb angle measurements in scol-iosis. Skeletal Radiol 1994;23:517-20.

210. Tibrewal SB, Pearcy MJ. Lumbar intervertebral disc heightsin normal subjects and patients with disc herniation. Spine1985;10:452-4.

211. Haas M. Reliability of reliability. J Manipulative PhysiolTher 1991;14:119-32.

212. Shrout PE, Fleiss JL. Intraclass correlation: uses in assessingrater reliability. Psychol Bull 1979;86:420-8.

213. Carr EK, Kenney FD, Wilson-Barnett J, Newham DJ. Inter-rater reliability of postural observation after stroke. ClinRehabil 1999;13:229-42.

214. Jones CJ, Rikli RE, Max J, Noffal G. The reliability andvalidity of a chair sit-and-reach test as a measure of ham-string flexibility in older adults. Res Q Exerc Sport 1998;69:338-43.

215. Benvenuti F, Mecacci R, Gineprari I, Bandinelli S, BenvenutiE, Ferrucci L, et al. Kinematic characteristics of standing dis-equilibrium: reliability and validity of a posturographic pro-tocol. Arch Phys Med Rehabil 1999;80:278-87.

216. Burdorf A. Reducing random measurement error in assessingpostural load on the back in epidemiologic surveys. Scand JWork Environ Health 1995;21:15-23.

217. Burt S, Punnett L. Evaluation of interrater reliability for pos-ture observations in a field study. Appl Ergon 1999;30:121-35.

218. Lu TW, O’Connor JJ. Bone position estimation from skinmarker co-ordinates using a global optimisation with jointconstraints. J Biomech 1999;32:129-34.

219. Jette AM, Jette DU, Ng J, Plotkin DJ, Bach MA. Are perfor-mance-based measures sufficiently reliable for use in multi-center trials?: musculoskeletal impairment (MSI) studygroup. J Gerontol A Biol Sci Med 1999;54:M3-M6.

220. Downs FS, Fitzpatrick JJ. Preliminary investigation of thereliability and validity of a tool for the assessment of bodyposition and motor activity. Nurs Res 1976;25:404-8.

221. De La Huerta F, Leroux MA, Zabjek KF, Coillard C, RivardCH. Stereovideographic evaluation of the postural geometryof healthy and scoliotic patients. Ann Chir 1998;52:776-83.

222. Leskinen T, Hall C, Rauas S, Ulin S, Tonnes M, Viikari-Juntura E, et al. Validation of portable ergonomic observation(PEO) method using optoelectronic and video recordings.Appl Ergon 1997;28:75-83.

223. Pan CS, Gardner LI, Landsittel DP, Hendricks SA, Chiou SS,Punnett L. Ergonomic exposure assessment: an application ofthe PATH systematic observation method to retail workers.Postures, activities, tools, and handling. Int J Occup EnvironHealth 1999;5:79-87.

224. Harrison DD, Harrison SO, Croft AC, Harrison DE, Troy-



643

anovich SJ. Sitting biomechanics, II: optimal car driver’s seatand optimal driver’s spinal model. J Manipulative PhysiolTher 2000;23:37-47.

225. Mucha RF, Weiss RV, Mutz R. Detection of the erect positionin the freely-moving human: sensor characteristics, reliabili-ty, and validity. Physiol Behav 1997;61:293-300.

226. Ferrigno G, Baroni G, Pedotti A. Methodological and techno-logical implications of quantitative human movement analy-sis in long term space flights. J Biomech 1999;32:431-46.

227. Gaebler C, Kukla C, Breitenseher MJ, Nellas ZJ, Mittl-boeck M, Trattnig S, et al. Diagnosis of lateral ankle liga-ment injuries: comparison between talar tilt, MRI and oper-ative findings in 112 athletes. Acta Orthop Scand 1997;68:286-90.

228. Luoto S, Aalto H, Taimela S, Hurri H, Pyykko I, Alaranta H.One-footed and externally disturbed two-footed posturalcontrol in patients with chronic low back pain and healthycontrol subjects: a controlled study follow-up. Spine 1998;23:2081-9.

229. Kilbom A. Assessment of physical exposure in relation towork-related musculoskeletal disorders: what informationcan be obtained from systematic observations? Scand J WorkEnviron Health 1994;20(special number):30-45.

230. Griegel-Morris P, Larson K, Mueller-Klaus K, Oatis CA.Incidence of common postural abnormalities in the cervical,shoulder, and thoracic regions and their association with painin two age groups of healthy subjects. Phys Ther 1992;72:425-31.

231. Brau BL, Amundson LR. Quantitative assessment of head andshoulder posture. Arch Phys Med Rehabil 1989;70:322-9.

232. Lantz CA, Chen J, Buch D. Clinical validity and stabilityof active and passive cervical range of motion with regardto total and unilateral uniplanar motion. Spine 1999;24:1082-9.

233. Petersib Dem Blankenship KR, Robb JB, Walker MJ, BryanJM, Stetts DM, Mincey LM, et al. Investigation of the validityand reliability of four objective techniques for measuring for-ward shoulder posture. J Orthop Sports Phys Ther 1997;25:34-42.

234. Greenfield B, Catlin PA, Coats PW, Green E, McDonald JJ,North C. Posture in patients with shoulder overuse injuriesand healthy individuals. J Orthop Sports Phys Ther 1995;21:287-95.

235. McLean IP, Gillan MG, Ross JC, Aspden RM, Porter RW. Acomparison of methods for measuring trunk list: a simpleplumbline is the best. Spine 1996;21:1667-70.

236. Crowell RD, Cummings GS, Walker JR, Tillman LJ.Intratester and intertester reliability and validity of measuresof innominate bone inclination. J Orthop Sports Phys Ther1994;20:88-97.

237. Torburn L, Perry J, Gronley JK. Assessment of rearfoot mo-tion: passive positioning, one-legged standing, gait. FootAnkle Int 1998;19:688-93.

238. Gross MT, Burns CB, Chapman SW, Hudson CJ, CurtisHS, Lehmann JR, et al. Reliability and validity of rigid liftand pelvic leveling device method in assessing functionalleg length inequality. J Orthop Sports Phys Ther 1998;27:285-94.

239. Brouwer B, Culham EG, Liston RA, Grant T. Normal vari-ability of postural measures: implications for the reliability ofrelative balance performance outcomes. Scand J Rehabil Med1998;30:131-7.

240. Dao TV, Labelle H, Le Blanc R. Intra-observer variability ofmeasurement of posture with three-dimensional digitization.Ann Chir 1997;51:848-53.

241. Baker CP, Newstead AH, Mossberg KA, Nicodemus CL.Reliability of static standing balance in nondisabled children.Pediatr Rehabil 1998;2:15-20.

242. Ployon A, Lavaste F, Maurel N, Skalli W, Dubousset J, ZellerR, et al. A protocol of in vivo 3D experimental evaluation ofglobal posture and motion of the spine. Rev Chir OrthopReparatrice Appar Mot 1997;83:719-29.

243. Westcott SL, Lowes LP, Richardson PK. Evaluation of pos-tural stability in children: current theories and assessmenttools. Phys Ther 1997;77:629-45.

244. Harrison AL, Barry-Greb T, Wojtowicz G. Clinical measure-ment of head and shoulder posture variables. J Orthop SportsPhys Ther 1996;23:353-61.

245. Watson AW. Sports injuries in footballers related to defects ofposture and body mechanics. J Sports Med Phys Fitness1995;35:289-94.

246. Liu SH, Lawson D. Power spectrum of the fast Fourier trans-form for measurement of standing balance. Aust J Sci MedSport 1995;27:62-7.

247. Lundstrom A, Lundstrom F, Lebret LM, Moorrees CF.Natural head position and natural head orientation: basic con-siderations in cephalometric analysis and research. Eur JOrthod 1995;17:111-20.

248. Garrett TR, Youdas JW, Madson TJ. Reliability of measuringforward head posture in a clinical setting. J Orthop SportsPhys Ther 1993;17:155-60.

249. Alviso DJ, Dong GT, Lentell GL. Intertester reliability formeasuring pelvic tilt in standing. Phys Ther 1988;68:1347-51.

250. Gajdosik R, Simpson R, Smith R, DonTigny RL. Pelvic tilt.Intratester reliability of measuring the standing position andrange of motion. Phys Ther 1985;65:169-74.

251. Vernon H. An assessment of the intra-and inter-reliability ofthe postureometer. J Manipulative Physiol Ther 1983;6:57-60.

252. Dai K, Gu J. Quantitative evaluation of human balance and itssignificance. Chung Hua I Hsueh Tsa Chih (Taipei) 1990;70:450-2.

253. Raine S, Twomey LT. Head and shoulder posture variations in160 asymptomatic women and men. Arch Phys Med Rehabil1997;78:1215-23.

254. Riegger-Krugh C, Keysor JJ. Skeletal malalignments of thelower quarter; correlated and compensatory motions and pos-tures. J Orthop Sports Phys Ther 1996;23:164-70.

255. Fialka-Moser V, Uher EM, Lack W. Postural disorders inchildren and adolescents. Wien Med Wochenschr 1994;144:577-92.

256. Peterson B, editor. Postural balance and imbalance. Newark,Ohio: American Academy of Osteopathy; 1983.

257. Beaudoin L, Zabjek KF, Leroux MA, Coillard C, Rivard CH.Acute systematic and variable postural adaptations inducedby an orthopaedic shoe lift in control subjects. Eur Spine J1999;8:40-5.

258. Keppler P, Strecker W, Kinzl L. Analysis of leg geometry:standard techniques and normal values. Chirurg 1998;69:1141-52. (Ger).

259. Lawrence DJ. The year book of chiropractic. St Louis:Mosby; 1993. p 184.

260. Balon JB, Aker PD, Crowther ER, Danielson C, Cox PG,O’Shaughnessy D, et al. A comparison of active and simulat-ed chiropractic manipulation as adjunctive treatment forchildhood asthma. N Eng J Med 1998;339:1013-20.

261. LeBouef C, Brown P, Herman A, Leembruggen K, Walton D,Crisp TC. Chiropractic care of children with nocturnal enure-sis: a prospective outcome study. J Manipulative Physiol Ther1991;14:110-5.

262. Harrison DE, Cailliet R, Harrison DD, Troyanovich SJ,Harrison SO. A review of biomechanics of the central nervoussystem, I: spinal canal deformations due to changes in pos-ture. J Manipulative Physiol Ther 1999;22:227-34.

263. Harrison DE, Cailliet R, Harrison DD, Troyanovich SJ,Harrison SO. A review of biomechanics of the central ner-


644

vous system, II: strains in the spinal cord from postural loads.J Manipulative Physiol Ther 1999;22:322-32.

264. Harrison DE, Cailliet R, Harrison DD, Troyanovich SJ,Harrison SO. A review of biomechanics of the central ner-vous system, III: spinal cord stresses from postural loads andtheir neurologic effects. J Manipulative Physiol Ther 1999;22:399-410.

265. Beer FP, Johnston ER. Mechanics of materials. 2nd ed. NewYork: McGraw-Hill; 1992.

266. Friedberg SH, Insel AJ, Spence LE. Linear algebra. 2nd ed.Englewood Cliffs: Prentice Hall; 1989.

267. Morgan L. The routine use of radiographic spinal displacementanalysis: a dissent [letter to the editor]. J Manipulative PhysiolTher 1999;22:548.

A Normal Spinal Position: It's Time to Accept the Evidence

Health & Medicine

Transcript of A Normal Spinal Position: It's Time to Accept the Evidence