Yudu - sportEX medicine - 1999-2010

CLINICAL EXAMINATION TECHNIQUES EXAMINATION OF THE SHOULDER By Dr Nick Webborn, Dip.Sp.Med

Anatomy Although we refer to the glenohumeral joint as the shoulder joint, it is important to appreciate that corresponding movement must occur in the sternoclavicular, acromioclavicular and scapulotho- racic joints for normal function. The combined movement is often referred to as the ‘scapulohumeral rhythm’ and ensures the cora- coacromial arch swings out of the way of the elevating humerus and prevents impingement.

Features of the glenohumeral joint ● It has little intrinsic joint stability because of the shallow

socket. Additional stability is provided by: a) static restraints – ligaments b) dynamic restraints – predominantly the rotator cuff muscles

● The glenoid cartilage is thinner at the centre than at the periphery

● The fibrous labrum adds approximately 1 cm to the glenoid diameter, but little or no additional joint stability is attribut- able to the labrum itself.

a) Static stabilisers (Fig.1) i) Superior glenohumeral ligament - this is the primary restraint to inferior translation (see Sulcus sign later) ii) Middle glenohumeral ligament - intermediary role according to arm position eg. resistance to anterior translation with arm abducted to 45º iii) Inferior glenohumeral ligament - primary restraint to anterior and anteroinferior instability. It consists of anterior and posteri- or bands and an axillary pouch. These act as a hammock-like structure supporting the head of the humerus in abduction with internal or external rotation

The three glenohumeral ligaments, coraco-humeral ligaments and the joint capsule are positioned in a finely tuned, interrelated pattern to achieve static joint stability.

b) Dynamic stabilisers (Fig.2) i) The rotator cuff – maintaining the head of the humerus on a moving platform. The rotator cuff acts as a force couple to sta- bilise the joint’s centre of rotation during movement ii) Deltoid - primary force causing displacement. An imbalance between deltoid and rotator cuff can lead to impingement iii) Infraspinatus is the primary muscle force responsible for exter- nal rotation when the arm is in a position of anterior instability (90º abduction and 90º external rotation) iv) Scapular stabilisers and the balance between them – including serratus anterior, trapezius (and the balance between upper and lower fibres), the rhomboids and levator scapulae

History Prior to any physical examination a full history should be taken. ● Age of the patient – this will make certain diagnoses more like- ly eg. rotator cuff pathology in the older patient versus ante- rior instability in the young patient after a fall

● Occupation – do they spend eight hours using a PC each day or drive a few hundred miles per week

● Sport participation – level, experience in sport, technical fac- tors

● Acute injury versus gradual onset • mechanism of injury • abduction external rotation for dislocation • fall on point of shoulder for A-C joint injury • phase of throwing or swimming when pain occurs • radiation of pain or neurological signs • previous history of neck pain or injury • changes in training pattern

Superior Middle Inferior

Gleno- humeral ligament

Deltoid Infraspinatus

Teres minor

Teres major

Trapezius

Latissimus dorsi

Figure 1: Close up of the main ligaments responsible for stabilisation of the glenohumeral joint (posterior view)

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Figure 2: Main muscles responsible for stabilisation of the glenohumeral joint (posterior view)