The shoulder consists of two joints:
- Glenohumeral (ball and socket)
- Acromioclavicular (collarbone/shoulder blade)
The glenohumeral joint is the most mobile joint in the body and many injuries are related to this significant mobility. For example the rotator cuff muscles stabilize the ball and socket when the shoulder is moving and repetitive overhead positioning can stress or even tear the superiorly placed supraspinatus tendon. Common diagnoses in this subgroup include:
- Partial or complete rotator cuff tears
- Tendonitis, Bursitis
- Impingement syndrome
- Labral tears (Throwers shoulder)
- Shoulder arthritis (Particularly the acromioclavicular joint.)
If the shoulder is forced beyond its range of motion then the ball can slip out of the socket and a dislocation results.
If the ball almost slips out but self-reduces this is call a subluxation.
The acromioclavicular joint is the anatomic portion involved in the shoulder separations. A direct blow to the point of the shoulder sprains the joint and if move severe, ligaments tear causing the clavicle to separate upwards. If this joint is chronically sprained, the joint becomes arthritis, by far the most common arthritis of the shoulder region.
Most shoulder conditions are amenable to conservative treatment with specific physical therapy conditioning, the key to prevention. Temporary change in activities (rest), anti-inflammatories and sometimes corticosteroid injections are successful treatment options.
However if surgical intervention is necessary almost all shoulder conditions can be addressed by arthroscopy.