Shoulder Pain

Shoulder pain is such a common problem that family physicians and orthopedic surgeons alike both see patients with various types of shoulder pain daily in the office. The shoulder is one of the most complex joints in the body. It has more mobility and less stability than nearly every other joint. I describe the shoulder joint as a lousy ball and socket. The socket is so shallow that if it were not for the muscles, tendons and the labrum that hold the shoulder in its place it would simply fall out of socket. This has the advantage of making the shoulder a very dynamic joint.

The socket of the shoulder is called the acetabulum, and is a cupped area on the shoulder blade or scapula where the head of the humerus joins the shoulder. Around the edge of the acetabulum is a cartilage called the labrum that is a key feature that holds the ball in its socket. The labrum is relatively weak in this role, and depends on many muscles and tendons that collectively are called the rotator cuff to keep the shoulder joint intact. You have likely heard or people having a rotator cuff tear. This is really a name for many different types of shoulder injuries. Any of the tendons or muscles that constitute the rotator cuff can become frayed, or completely torn, and when this happens it's called a rotator cuff tear.

At least as common as rotator cuff tears are inflammatory problems of the shoulder. The long head of the biceps tendon comes up in front of the shoulder from the upper arm, and commonly becomes inflamed from overuse or strain. This is called biceps tendinitis and is one of the most common causes of anterior shoulder pain. The supraspinatus tendon on the back top of the shoulder can become inflamed causing supraspinatus tendinitis. The bursa, or lubricating sac that lies under the deltoid muscle on the point of the shoulder can become inflamed causing deltoid bursitis.

The joint between the collar bone, or clavicle, and the most anterior part of the shoulder blade is called the acromioclavicular joint. It can become torn or partly torn by a blow to the top of the shoulder, causing an acromioclavicular, or AC tear. This is commonly called a separated shoulder. This joint also commonly becomes arthritis in middle aged and older persons, and there is a bursa under this joint that can become inflamed and is called subacromial bursitis.