Oct/Nov 2007 - Page 30

Part One on this subject explained that there were twocategories of ‘headshaker’ - those suffering from

Headshaking Syndrome and those suffering from one ormore other influences that cause head tossing, shaking or noddingbehaviour. It discussed Headshaking Syndrome in detail, includinghow and why the condition is thought to develop and the varioustreatment options available. Now, in this issue and a future one, theaim is to move on to explore some of the other main health andtraining issues that can be underlying factors.

Although the three perspectives - dentistry, craniosacral andbehavioural - to be presented vary in some respects, all three of the

experts consulted agree emphatically on one point; that EVERYpotential cause of head shaking, nodding and tossing needs to be

thoroughly assessed. It is therefore likely that a number ofpractitioners (as well as the owner) will need to be involved

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Continued

Oct/Nov 2007 - Page 32

THE DENTISTRY ASPECTand to work together to come up with thebest possible plan for overcoming theproblem. There is little to be gained if a‘headshaker’ undergoes a program ofbehavioural re-training without first havingits mouth examined from a dentalperspective, assessment to rule out thepossibility of an injury to the skull and thefit of its gear checked.Then, of course, executing the remedial planfor a headshaking case is likely to requiretime, patience and persistence on everyone’spart as, in the majority of cases, there is no‘quick fix’. In fact, the longer a horse hasbeen exhibiting abnormal head movements,the more likely it is to have developed amulti-faceted problem.

The types of dental problems that contributeto head shaking or head tossing may relateto the horse’s age, in that younger horses(1-6 years) are still erupting adult teeth and,during this process, may show signsassociated with pain. Usually, in this agegroup, any pain being experienced is dueeither to the shedding of teeth, an impactedtooth or sharp slivers of tooth roots left inthe gum after teeth have been shed.Horses of all ages may exhibit head tossingbehaviour due to presence of upper wolfteeth, although this will usually beassociated with a bit being in the mouth, orcan suffer from fractures to the facial bones- most particularly, the jaw. Also, asmentioned in Part One of this article, equineteeth are innervated by (obtain their nervesupply from) the trigeminal nerve, whichbranches to supply the upper and lower teethand the area around them - meaning thatpain causing head tossing or shaking maybe able to be traced back to this source.Dentistry DiagnosisExposure of the sensitive dentinal tubuleswithin the teeth can cause pain and

All Shook Up part 2 cont....

Each horse’s mouth is individual as to specific spaceavailable for the bit, and the fit of the bridle and size ofbit selected can be a direct link to head shaking.Right: These wire cuts under the horse’s tonguehighlight the need for a thorough examination of thosethat exhibit head -shaking behaviour. P

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sensitivity which can be very hard to detectand diagnose, therefore a thoroughexamination of the mouth (‘oral exam’) witha quality light source is essential. Whiledoing this, ice cold water may be applied tospecific teeth to see what responses (forexample, a rapid movement that mayindicate pain) can be obtained from thehorse. Nerve blocks, performed by aveterinarian, may also be required toconfirm if a response is due to nerve pain.The surfaces of all the teeth should also beclosely and thoroughly examined with adental mirror to detect any abnormalities,and the interior of the mouth carefullyassessed for any signs of ulceration to thecheeks and gums. These types ofinvestigations can often reveal conditionsthat have gone undiagnosed for years, oftenwhile the owner of a ‘head shaker’ haspursued many other time-consuming andcostly avenues of treatment to no avail. Forexample, a recent case at my practice saw ahorse that exhibited head shaking behaviourbeing diagnosed with a 10cm diameter ulcerof its cheek caused by a previous fracturedtooth pressing into the gum.Another frequent cause of head nodding,tossing or shaking behaviour from thedentistry perspective is the presence offoreign bodies - like grass seeds and wire -in the mouth, which, again, can requirerepeated examinations with a good lightsource, a mirror and a dental probe todiagnose. Then, of course, the offendingitem must be removed and treatment toprevent or control infection administered bya veterinarian, along with a period of‘bitless’ rest and perhaps a modified dietbeing prescribed to allow the damaged areato heal.Finally, spaces (called diastema) candevelop between a horse’s teeth that thenoften become packed with trapped feed.This can later ferment, allowing the growthof bacteria which then attack the gum,leading to gum disease (gingivitis) anddamage (periodontal disease) to thestructures which support the teeth. Thesensation a horse experiences from thiswhole scenario can be likened to the feelingof having food trapped between our ownteeth, so it is little wonder that it attemptsto get rid of the annoying feeling by shakingor tossing its head.The good news, however, is that effectivetreatment exists for gingivitis and peridontaldisease. After a thorough assessment andmaybe radiographs being taken to determineif the affected tooth or teeth can be saved,the offending feed is removed then a seriesof burrs plus a high speed dental drill usedto widen the space to gum level. The area isthen flushed with an antibacterial solutionand the horse placed on systemic antibiotics.This whole procedure is best done by aveterinarian with specialist skills indentistry, due to the prescription of

so care must be taken not to use a thickmouthpiece on a horse that has a small oralcavity. Often, owners make the mistake ofthinking that ‘the thicker the bit, the kinderit is’ but horses must be able to have releasefrom pressure and a thick bit in a smallmouth may make this impossible.Another observation from a dentistryperspective that may be made during anexamination of a ‘head-shakers’ mouth isthat it may react specifically to stimulationof the tongue. This can have furtherimplications in terms of the fit of the bit andbridle as, for example, the bit may need tobe adjusted higher or lower, a differentlyshaped bit may have a less irritatinginfluence or a bit made from a differentmaterial may create a more palatable andpleasant feeling for the horse - thuslessening the likelihood of head tossing orshaking. Techniques such as riding bitlessand lungeing in a halter can help to pinpointwhether a headshaking problem is bit and/or tongue related, then it’s a process of trialand error to work out the most comfortableand effective bridling solution.

THE CRANIOSACRALPERSPECTIVE

All Shook Up part 2 cont....

Bottom: This head-shaking horse had multiplecuts including a cut to the gums behind theincisors and a large cut under the tongue, causedby either poor quality feed or a foreign body suchas wire.Photos courtesy Dr Shannon Lee

Right: Prevention may be better than a cure forhead-shaking. If the impacted incisor caps inthis three year old’s mouth are not correctednow it could have lifelong problems.

Below: A dental mirror is used to assess the teethand mouth for any abnormalities.

Below centre: Food trapped between teeth canbe a source of annoyance to the horse as well asleading to gum disease and head shaking.

In order to understand head shaking and itscauses, it is important to realise that ahorse’s skull (or cranium) is constantlyexposed to more pressures than is any otherpart of the body. These pressures arepredominantly applied by items such as bits,bridles and nosebands - often not fittedproperly - or may arise from invasiveprocedures on the head, such as dental workor trauma, such as a head injury. As a result,there are compressive ‘flow-on’ effects to theindividual bones of the skull, the surroundingsoft tissue or muscles and the cranial nerves,which may ultimately contribute to theformation of a head shaking response.TIGHT AND TENDERCraniosacral therapy, a gentle and non-invasive technique using extremely lightfinger pressure, aims to feel and addressimbalances in the body of the muscular-skeletal system by acting on what is known

medication and sedation being a ‘vet only’domain.Equipment IssuesAnother potential cause of head shaking istack - more specifically, the bit and bridle -as few owners take the time to properlyassess the fit of these items. Horse’s mouthsare very individual, especially in terms ofthe space available to accommodate a bit,

Oct/Nov 2007 - Page 35

A pioneer in her field,American practitionerMaureen Rogers is thefounder of EquineCraniosacral Workshopsand travels extensively toteach, lecture and provideprivate consultations. Herequine clients come froma range of disciplinesincluding eventing,

HEAD INJURIESHead injuries and trauma, whether recentor sustained in the past, can tend to bedismissed or overlooked as a possiblesource of headshaking, yet craniosacraltherapists often focus their treatment in thisdirection with success. Take the case ofHektor - a Thoroughbred gelding that hadbeen violently head shaking for more thannine years after his condition was firstnoticed in the spring of 1991. Despite beingtreated with antihistimines, steroids,chiropractic and acupuncture, he hadbecome unrideable by 2000 - which waswhen his owners sought assistance from thecraniosacral perspective.Subsequently, it was discovered that Hektorhad suffered a head trauma as a young horse,resulting in compression to his right nasalbone, frontal bone, sphenoid and maxilla.To make matters worse, in 1995, he hadanother head injury in which he lost twofront teeth. The combination of bothtraumatic incidents had also left him withchronic swelling of the tissues that line theinside of the upper airway, which saw himsuffering from allergy-like symptoms.Once craniosacral therapy had beenimplemented to ‘release’ the traumatisedareas of his skull, Hektor showed significantimprovement from the very first session. Histreatment continued for eighteen months,during which there was a markedimprovement in the frequency and intensityof his headshaking episodes, and he is nowhead-shaking free although does still benefitfrom craniosacral treatments.Hektor’s case is a perfect example of aphenomena that is an important principle

for craniosacral work, which is that bone ishealthy, living tissue therefore any pressureput on it will affect how it develops andshapes itself. Nowhere in the body is thismore relevant than in the skull which, ratherone being one solid bone as one mightimagine, is actually made up of a numberof bony plates separated by sutures, whichact like joints. These sutures - especially inhorses less than five years of age due thebones still changing shape from growth andtooth eruption and development - allow fora certain degree of movement and somedispersal of impact if a blow to the head isexperienced but they can also become‘jammed’ by unnatural sources of pressuresuch as the tight noseband, ill-fitiing bit orbridle and dentistry work mentioned above.PRESSURE IDENTIFICATIONCraniosacral therapy, in itself, can onlyprovide part of the solution to a headshakingproblem as, in order for this condition tofully resolve, one must truthfully look at andaddress all the elements that may haveattributed to creating it. It may sound basicbut if steps are taken to ensure that bits andbridles fit correctly, nosebands are kept asloose as possible and regular, professionaldental work and check ups are carried out,this will lessen the likelihood ofheadshaking developing in the first place.Looking at every factor in terms of how itmight be increasing the amount of pressureand irritation within the head - especiallyon the skull - plus considering how all theselittle bits of extra pressure could be addingup to ‘one big headache’ can be quiteenlightening!Addressing potential imbalances arisingfrom tightness in the soft tissues - such asafter intensive dental work or at regularintervals during a rigorous training regime- is equally important to create balance andhealthy biomechanics in a horse. If this isn’tdone, the pressure on the cranial bones andimportant joints in the head such as the TMJwill continue to build up and any headshakingbehaviour to worsen over time.

Part Three, in a future issue, will containadvice on how headshaking develops froma behavioural perspective and what can bedone to address this via re-training.

as the craniosacral system - that is, the head,tailbone, spinal cord and spinal dura (theprotective sheath surrounding the spinalcord).When performed on horses that ‘headshake’,craniosacral therapy focuses on ‘opening up’structures in the head that are being’tightened’by excessive practices creating abnormalcompressive forces. An example of this typeof force is pressure being applied to the jawby bit pressure or the muzzle area by a tightnoseband, which will usually cause a horseto constantly try to open its mouth. This actiontends to lead to increased muscle tension, achange in mastication (chewing) patterns and,ultimately, interference with the normalfunction of the temporomandibular (TMJ)joint.As time goes on in the ‘noseband’ and bitscenario, the tight muscles associated withthe TMJ joint and the bones of the craniumbegin to put direct pressures on the temporalbone, where the trigeminal nerve is housed.(As was explained in Part One of this article,irritation to the trigeminal nerve is consideredby some to be one of the major causativefactors in the whole clinical picture ofheadshaking). Craniosacral therapists believethat, if the degree of pressure on the temporalbone becomes high enough, trigeminal nervecan become ‘pinched’ due to tightening ofthe surrounding tissue - creating a ‘burning’type of pain or intermittent ‘shooting’ of sharppain in the head. This situation closely equateswith how a migraine headache develops andfeels in a human but, unfortunately, it isn’teasy for a horse to ‘pop a pill’ or race off tothe physio when it feels one coming on!Headshaking, it seems, may simply be oneway a horse tries to find relief.OTHER PRESSURE SOURCESAs pressure is applied incorrectly or to anincorrectly fitted bit via the reins, a horsewill close its jaw (mandible) and pushagainst the pressure of the bit - thusshortening and tightening the muscles ofmastication (chewing), especially thetemporalis and masseter muscles. Similarto what develops from wearing a tightnoseband, this muscular imbalance thenaffects the TMJ joint, which then puts stresson the bones of the cranium and surroundingnerves - potentially causing pain. A tight orpoorly fitted bridle creates much the samepicture except, on this occasion, the initialpressure is usually applied to theatlantocciptial joint at base of the skull.There is no denying that dental work isessential for a horse’s overall well-being anddefinitely no suggestion from craniosacraltherapists that it shouldn’t be carried out but,at the same time, these procedures do resultin increased pressures being applied to thecranial bones and surrounding muscles. Thismainly occurs through the horse ‘bitingdown’ on the gag for an extended period oftime or via forces generated by the use ofhand or power tools.

The sutures,which act likejoints, canbecome‘jammed’ byunnaturalsources ofpressure (rightand below)such as thetight noseband,ill-fitiing bit orbridle.

If the pressure on the temporalbone becomes high enough, the

trigeminal nerve can become‘pinched’ - creating pain similiar to

a ‘migraine headache’.

trigeminal nerve

temporomandibularjoint ( jaw joint)

Maureen Rogers - craniosacral

dressage, barrel racing and pleasure riding. She is also theauthor of internationally published articles and haspresented at major equestrian education events such asEquitana Asia Pacific.