understanding the shoulder article-2014.doc

8/10/2019 Understanding the Shoulder article-2014.doc

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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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%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

Common in"uries and causes

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There 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 eitheprimary 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 cu9supraspinatus tendobeneath the

coracromial 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.

:eakness of scapulothoracicmuscles leads to abnormal positioning of thscapula.

b' otator cu2 repairMechanism 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


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:ith aging0degenerative1, the farthest portion of the supraspinatus tendon iparticularlyvulnerable to impingement or stress from overuse. =steophytes0;alci*cationdeposits1develop resulting in decreased sub acromial space leading to continuous micro

trauma andeventual gradual tears.

In -thletes, weakness of the rotator cu0supraspinatus, infraspinatus particuresults

in humeral head repositioning superiorly0up1 impinging the rotator cu0!T;1.This impingement leads to degenerative changes and gradual or sudden tears r

Medical treatment:Indications for surgery, include failure to make progress a

to > months of conservative care, or an acute full


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wall 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

%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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Scapular retractionexercises such as mid row with cable machine and ltrape(iusstrengthening will decrease the load to front of the shoulder.

#0ternal rotation strengthening2 ideal is side lying which is more isolafor

teres minor and infraspinatus recruitment0decreases the load to the antershoulder1.

%igure *' Seated mid ro/ e0er

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

#0ercises ?@!A#A /ith impingement syndrome:

Behind the nec; press e0ercise


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b' otator cu2 repairecommendations for rotator cu2 training: 5xtremely important to consu

/ith@rthopedic surgeon7supervising@6 as well as client)s physical therapist to

determine atwhat stage the person is. &pper body e0ercises that are safebased onbiomechanics include2

$ow trap pull downs with cable standing or tubing

4eated mid row, one arm 6B row, seated reverse yes0posterior deltoid1

5xternal rotation with cable9tubing, seated reverse yes, seated dumbbelraises0once medically cleared and at least % months tissue healing1

;ore strengthening exercises that are safe includestanding trunk rotatiowithcable9tubing, diagonal with cable tandem in place lunge, planks, planks wball, trunkrotation with forward lunge.

#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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SummaryThe shoulder is a complex unit that is comprised of a multitude ofligaments, tendons, connective tissue, muscles that synergisticallyinitiate and correct movement, and stabili(e when an unstableenvironment. &nderstanding the anatomy, biomechanics and weak

linksof the shoulder, common injuries and evidenced based trainingstrategies, should provide you with the insight to better understandand work with clients with these kind of injuries more con*dently.

;hris is the ;5= of 3innacle Training C ;onsulting 4ystems03T;41. -continuing education company, that provides educational material inthe forms of home study courses, live seminars, 6D6s, webinars,articles and min books teaching in"#


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and Joint Surgery,vol. 8


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#. -natomically, what tendon is located below the subdeltoid bursaKa. Bicep tendonb. Infraspinatus tendonc' Supraspinatus tendond. 3atellar tendon

%. :hat is the most common mechanism of injury for someone tosuer a rotator cu tearK

a. 3oor postureb' Traumac. =veruse onlyd. one of the above

'. :hich of the following muscles is the most often injured per theresearchK a. 4ubscapularis

b. Infraspinatusc. Teres minord' Supraspinatus

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

shoulder impingement syndrome e0ceptDa. 4i(e of acromionb. :eak scapulothoracic musclesc. Tight posterior capsuled. Tightness in pectorals, anterior deltoid

e' 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. :hich 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 triceppressdo/ns

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b. 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 pulldownmachine, standing cable external rotation, tricep pressdowns,

planksd. Barbell s+uats, one arm 6B row, seated chest press machine,seated 6B side raises,single arm tricep 6B kickbacks, bridging with physioball.

8. -ll of the following is a contributing factor that can possibly cause anon traumatic rotator cu tear, e0ceptD

a. =steophytesb. !epetitive unilateral loads or liftingc. :eakness in supraspinatus, particularly in athletesd' Performing chest e0ercises t/ice a /ee; and forgetting to

stretch

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understanding the shoulder article-2014.doc

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