Anatomy of Shoulder Sport

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Anatomy of sports related

shoulder problems

Prof P Bala

National University of Singapore


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Common sports relatedproblems of shoulder

Rotator cuff tendinitis

Impingement

Rotator cuff tears mechanical Frozen shoulder non-mechanical

Instability, dislocation

Nerve injuries Non-sports related problems


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Shoulder Problems: clinicalcomplaint

Pain: local or referred

Stiffness , painful arc

Instability Weakness

Drop arm syndrome


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Shoulder : clinical presentation

To understand the pathology, clinicalfeatures, diagnostic imaging and treatment

A knowledge of shoulder anatomy isnecessary.

Otherwise we will be treating images


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The shoulder

A region that connects neck, trunk andupper limb to place hand in space

Enjoys greater freedom of motion

Relies on muscles and ligaments forstability

To achieve its function, shoulder built upon 3 bones and 4 joints


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Use of shoulder in sports

Power ,speed and drive for

Throwing, pitching, tennis stroke, spiking,gymnastics , weight lifting, swimming etc.

Shoulder acceleration and decelerationare demanding actions in overhead throw

Overuse and excessive load

rotatorcuff failure, proximal head migrationand instability


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Shoulder anatomy

Is a 5 jointed system consisting of

Scapulothoracic joint

Acromiothoracic joint Sternoclavicular joint

Coracoclavicular joint syndesmosis

Glenohumeral joint


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Shoulder muscles

Motorised by 3 groups of muscles

Axio-scapulartrapezius, lev scapulae,rhomboids, serratus anterior

Axio-humeral---pec major&minor,lat dorsi

Glenohumeralsubscapularis,supraspinatus, infraspinatus, teres minor


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Scapular muscles and movement

2 functionsprovide stability of scapulawhen shoulder complex is loaded.

-movement of scapulapointing itself

under the humeral head to maintain properlever length and functional length of musls.

Provides the fulcrum to elevate the arm in

all planes Scapular motion by a force couple on a

moving platformthe glenoid


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Scapulo-humeral rhythm

During the first 30 deg of abd scapularmovement is only 1/5 of GH movement

Beyond 30 deg: 1 deg for every 2 deg ofmovement of humerus.

The synchrony of GH and SC-Thmotion produces mobility without loss ofstability


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Scapulo-humeral muscles

In 2 sleeves

Outer sleeve: deltoid & teres major

Inner sleeve : subscapularis

supraspinatus rotator cuff

infraspinatus

teres minor

The 2 sleeves glide on each other

Subacromial bursa gliding mechanism


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Role of rotator cuff and capsularligaments

GH joint lacks bony stability as in hip

Flat glenoid, no stability for a large head

Only little contact, yet great stability

Due to 2 factors-ability of scapula to rotateand support humeral head

Efficiency of soft tissues enveloping head.

Contraction of this group maintains the Hhead in constant contact with glenoid.


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Stability of GH joint

Atmospheric pressure

Glenoid fossa and labrumchock effect

Glenohumeral ligaments and long head ofbiceps attached to labrum

Inferior GH ligament complex like ahammock supporting head in abd and ext.

rotation Middle GH ligament acts like a check rein

to prevent posterior translation


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Stability of GH joint ctd

Superior GH ligament restricts inferiortranslation

Collectively the capsular ligaments and

labrum are static stabilizers Dynamic stability by rotator cuff and long

head of biceps

A thrower relies on dynamic effect ofrotator cuff for joint compression to avoidcapsule stretching


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Glenoid labrum and tears

Common in throwers

Large compression and shearingforces drive the head anteriorly andposteriorly

Creating traumatic cartilage injury andlabral tear

Three types of surface motion at GH joint

Rotation, rolling and translation (gliding)


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Subacromial space and bursa

Subacromial space is inferior to acromion,A-C joint, and coracoacromial ligament

Subacromial bursa lies in the sub acrom.space, between the acromion process andthe coracoacromial ligament above andthe GH joint below

The bursa cushions the rotator cuff

from the overlying acromion


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Subacromial space

Acromion type- 3 has downward pointingspur

Basis for anterior acromioplasty

Sourcil sign: sclerosis on theundersurface of acromion( eyebrow) dueto chronic rotator disease

GH joint and sub acromial space maycommunicate in ch rotator cuff disease


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Long tendon of biceps

Attached to the supraglenoid tubercle

Intrasynovial

Biciptal tendinitis SLAP tear type 2,3 & 4 involve the biceps

tendon


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Nerves , shoulder and sports

Thoracic outlet syndrome

Scapular neuropathy in volleyball players

Denervation of infraspinatus, repeatedstretching during serving

Referred pain from neck ,heart,gallbaldder


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Coracoclavicular ligament/ joint

Is a syndesmosis

Strong conoid and trapezoid ligaments

This joint permits little movement Ligament torn in grade 3 dislocation of

acromioclavicular joint


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Summary

Shoulder is a complex joint system.

In the pursuit of speed and power

Its soft tissues mainly are injured Precise location of the source difficult.

A thorough knowledge of its anatomy

necessary to diagnose and treat them

Documents

Anatomy of Shoulder Sport