Understanding the Shoulder-CEU Article

8/10/2019 Understanding the Shoulder-CEU Article

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The shoulder: understanding the sciencebehind both movement and dysfunction

By Chris Gellert, PT, MMusc & Sportsphysio, MPT,CSCS, MS

!ntroductionThe shoulder is a complex joint. That is involved in daily activities such as gettidressed orreaching into a cupboard. Because the shoulder is truly a ball and socket joint,providingit to move freely in six dierent motions, this makes it more susceptible to injurthis article,we will review the anatomy of the shoulder, common injuries to the shoulder,functional

assessments and training strategies to work with clients with previous shoulderinjuries.

The learning ob"ectives of this C#$ article are to:. !eview the functional anatomy and biomechanics of the shoulderand how it moves.

". Be able to understand the dierence between impingementsyndrome, rotator cu repair, and shoulder bursitis with respect tomechanism of injury and medical treatment of each condition.

#. $earn and be able to perform functional assessments of theshoulder.

%. &nderstand how the evidenced based research on how to trainclients who either have or had a history of impingement syndrome,rotator cu repair and bursitis.

'. Be able to design individuali(ed periodi(ed training programs, andunderstand recommended vs. contraindicated exercises for eachshoulder dysfunction that are practical and integrative in nature.

%unctional natomy$et)s look at two common functional tasks that everyone performs on a daily baThe *rst is getting dressed. The movement of putting a shirt on, biomechanicalre+uiresthe shoulder to undergo initial hori(ontal adduction, elbow exion, then shouldabduction andexternal rotation. -natomically, the posterior deltoid contracts during hori(ontaabduction,

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supraspinatus and medial deltoid abduct the shoulder, while teres minor andinfraspinatusexternally rotates the shoulder.a. etting dressed

%igure ' Getting dressed %igure (' Medial deltoid and supraspina

b. !eaching into cupboardThe process of reaching into the cupboard biomechanically re+uires shoulder as seenin the *gure below. /ere during shoulder exion, the humerus glidesinferiorly0down1 on theglenoid cavity. -natomically, the anterior deltoid and coracobrachialis ex theshoulder.

%igure )' %igure *' nterior %igure +' Coracobrachialiseaching into a cupboard deltoid

Basic anatomy

$et)s look at the shoulder anatomically There are four major joints within theshoulder complex,which include the glenohumeral joint, acromioclavicular joint, sternoclavicular andscapulothoracic joint.

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%igure -' .oints /ithin the shoulder comple0

MusclesThe four primary muscles that make up the rotator cu include2 supraspinatus,infraspinatus,teres minor and subscapularis. These four muscles provided stability and areinvolved in multipledaily activities, such as reaching, lifting, getting dressed and throwing a ball. 3research, thesupraspinatus muscle is the weakest of the four rotator cu muscles, is poorlyvasculari(ed andis the most often surgically repaired.

Supraspinatus muscle !nfraspinatus muscle Teres minor muscle

Subcapularis muscle4ide raises the arm 5xternally rotates the arm 5xternally rotates the armInternally rotates the arm

%igure 1' otator cu2 muscles

Biomechanics

. 6uring shoulder exion and abduction0side raising, there is (3degrees of movement that occurs at the glenohumeral joint and -3degreesat the scapulothoracic joint. This is called thescapulohumeral rhythm, 04/!1 as seen in *gure 7. 4/! is de*ned asthe movement relationship between the humerus and the scapuladuring arm raising movements.

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". -s seen in *gure 7, the humerus slides down in the glenoid cavityas the scapula rotates.

#. - force couple is formed during abduction0side raising1 of theshoulder. The importance of this force couple0*gure 81, is that when

these low trape(ius and searattus anterior are working synergistically,they biomechanically together cause upward rotation of the scapulaon the thorax. This upward rotation of the scapula on the thorax isre+uired to raise them arm to the side. Individuals suering fromimpingement syndrome and rotator cu repair have an altered rthymas seen in the *gure below.

%igure 4' 5ormal scapulohumeral rthym %igure 6' forcecouple is formed by the

low trape(ius andserratus anterior causing

upward rotation and glidingof the scapula on the thorax

%igure 3' bnormal scapular rthym

Muscle imbalances

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9hen physical therapists assess the shoulder and upper body, theupper trape(ius is typically tight and strong, however, the lowtrape(ius, rhomboids, external rotators are weak from a clinicalperspective. Based on this clinical information, it is important tostretch tight muscles, such as the upper trape(ius, then strengthen

the weak phasic muscles, such as the low trape(ius, rhomboids,serratus anterior, external rotators and scapular stabili(ers.

Common in"uries and causesThere are dierent types of injuries the shoulder can sustain. The most commonthe shoulderare impingement syndrome, rotator cu repair and sprain. In this next section, will revieweach condition providing a deeper understanding of each.a' !mpingement syndromeMechanism of in"ury7pathophysiology: 4houlder impingement may be eithe

primary orsecondary, diagnosed by physicians. There are two types of shoulder impingemwhich isdescribed below.

' Primary8Mechanical9 impingement2 Is caused by a mechanical dysfunctionas bursa,acromioclavicular joint, acromion, humerus or rotator cu:supraspinatus tendobeneath thecoracromial arch. This is a mechanicalproblem that may result from sub acromcrowding.

This can be directly attributed to the si(e or the acromion0typically type II or tyIII1.

(' Secondary8Structural9impingement2 Is caused by a relative decrease insubacromial spacecaused by instability of the glenohumeral joint, tight posterior capsule and weaofscapulothoracic musculature.

6ecrease in subacromial space comprises the supraspinatus tendon,

predisposing itto micro tears leading to degeneration and ultimately tearing.

Tightness of the posterior capsule causes the humerus to migrate into thacromioclavicular joint.

9eakness of scapulothoracicmuscles leads to abnormal positioning of thscapula.

b' otator cu2 repair

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Mechanism of in"ury7pathophysiology: ;ommonly occurs as a result of atraumaticaccident or fall and is graded from one to three in severity. They are classi*ed aacute,chronic, degenerative, partial or full months of conservative care, or an acute full


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%igure ' Shoulder bursitis

Common assessmentsThere are a few shoulder assessments that can prove to be eective.a' all Push up test

9ith men shirt o, women wearing a sports bra, have the client place arms showidth onwall with feet e+ual distance. Instruct them to lean forward0nose towards wall1 push backto starting position. *Look for shaking or juttering of shoulder(could indiceither weaknessor potential instability)

Winging of scapula indicates weakness of serratus anterior as seen in

gure below.

%igure (' all push up test

b' each behind bac; test

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%igure )' eaching behind their bac;

Instruct the client to reach behind their back and raise their hand as far asup towards

their spine.

@ark this0the spinal segment1


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%igure +' =o/ trape>ius /ith %igure -' Serratus anteriorsrengthening theratubing

#0ercises ?@!A#A /ith impingement syndrome: Behind the nec; press e0ercise


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#0ercises that are contraindicated include /ith rationale2

4eated 6B shoulder press0creates excessive load to the medial deltoid1.

$at pull downs behind the head0at end or range places greatest stress on glenohumeral ligaments as well as on the labrum1.

Barbell s+uats0places compressive and loading forces on the surgical gra

&pright row0at end of range


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years experience, with advanced training, has created over ?courses, is an experienced international *tness presenter, writes forvarious websites and international publications, consults and teachesseminars on human movement. For more information, please visitwww.pinnacle"#


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Jamamoto, -., et al., "??, G3revalence and risk factors of a rotatorcu tear in the generalpopulation,)Journal of Shoulder and !l"o# Surgery,vol.8, issue ,pp. >


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>. -ll of the following are contributing factors for developing forsomeone to develop

shoulder impingement syndrome e0ceptDa. 4i(e of acromionb. 9eak scapulothoracic muscles

c. Tight posterior capsuled. Tightness in pectorals, anterior deltoide' ll of the above are contributing factors

E. !eaching into a second shelf involves the recruitment of which ofthe following musclesK

a. -nterior deltoid onlyb. ;oracobrachialis onlyc' a and bd. @edial deltoid

7. 9hich of the following exercise programs is the most eective insomeone preventing someone to developing shoulder impingementK

a' =o/ trape>ius strengthening, mid ro/, seated chest press,seated reverse Eyes, standing # /ith cable, posteriorcapsule and pectoral stretching and standing tricep pressdo/nsb. Incline barbell chest press, kettle bell snatch, seated alternatebicep curls, standing front dumbbell raises, seated chest yemachine, performing rope exercisec. Flat bench barbell chest press, seated mid row, lat pull


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d. 4upine

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Understanding the Shoulder-CEU Article

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