Pain felt in the shoulder can come from a large number of potential sources. These include the neck, the shoulder itself, the heart, the lungs and conditions such as polymyalgia rheumatica.

The initial diagnosis is very important as it is essential to rule out serious causes and to focus on treating the correct underlying cause.

Shoulder Joint Anatomy

The shoulder is a ball and socket joint, but here the ball (humeral head) is extremely large and the socket (the glenoid) is small at around 25-30% the size of the ball and shallow. To help deepen the socket, it is surrounded by a fibrous rim called the glenoid labrum.

Shoulder Pain Detailed Anatomy

Another joint, which is considered part of the shoulder, is between the end of the clavicle (collar bone) and part of the shoulder blade. This is called the acromioclavicular joint.

The shoulder, unlike the hip, is a soft tissue joint. This means it relies for its stability and its mobility on the soft tissues such as ligaments, tendons and muscles. The shoulder has a large range of motion and little in the way of stabilising structures, making it a very mobile joint but not a stable one.

Shoulder Joint Problems

  • Acromioclavicular Joint Pain. This is usually in someone between 20 and 50 years old who has a history of dislocating or part dislocating the joint during sports or overhead activities. It is common in rugby.
  • Instability disorders. Mainly in people under 35 years old, there may be history of (part) dislocation in sport or with overhead work. Vague symptoms are common and limiting, with dead arm feelings.
  • Shoulder joint dislocation. Commonly done by falling on the arm with it out to the side. Requires medical attention.
  • Frozen Shoulder. More common over 40 years old, in diabetics and in women. Often the cause is not clear, the condition can be severe and take a long time to settle.
  • Rotator Cuff Disorders. Tend to occur in older people unless trauma is involved. Can be rotator cuff strains, rotator cuff tears or rotator cuff rupture.
  • Shoulder arthritis. Not common, it occurs in more elderly people or in people who have damaged the shoulder previously.
  • Fractures may occur to any of the shoulder joint bones, including a fractured clavicle, fractured neck of humerus or a fractured scapula (shoulder blade).
  • Glenoid labrum tears. The rim around the shoulder socket may get damaged and give symptoms.
  • Bursitis and tendonitis. Tendon strains or inflammation may occur in the long head of biceps tendon, the pectoralis major tendon, the supraspinatus tendon or other tendons. Bursitis may occur where someone has overused a movement greatly and inflamed the lubricating sacs between tissues.
  • Other Shoulder Conditions. These include wing scapula and suprascapular neuropathy.
  • Referred pain. Referred symptoms are symptoms that are felt in one area but generated in another. In the shoulder a common origin for pain is the neck. Neck pain should be excluded as a cause of shoulder problems.

References:

  1. NICE - Assessment of shoulder pain - http://cks.nice.org.uk/shoulder-pain#!scenario