Normal Anatomy

The glenohumeral (shoulder) joint is a highly mobile ball and socket joint, which consists of several components.

Bones

– scapula, clavicle, humerus

Rotator cuff muscles

– subscapularis, supraspinatus, infraspinatus, teres minor

Associated muscles

– deltoid, biceps and pectoralis

Ligaments

Joint capsule


Bony and X-Ray Features

These following pictures enlarge to show the bony features of the glenohumeral joint.

Normal Shoulder Joint (click to enlarge) Normal Shoulder Joint X-ray


Joint Stability

The stability of the enlocated joint depends upon four factors:

The suction cup effect of the glenoid labrum around the humeral head

Negative gleno-humeral intra-articular pressure and limited joint volume

Static stabilisers, including labrum, ligaments and joint capsule

Dynamic stabilizers especially rotator cuff and biceps muscles


Scapula Postion

It’s easy to forget scapula position, but this is one of the most crucial things to think about when you relocate a shoulder!  Review the anatomical differences between the retroverted and anterverted scapula here.

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