Understanding Shoulder Pain

Shoulder problems, including pain, are one of the more common reasons for physician visits for musculoskeletal symptoms.

The shoulder is the most movable joint in the body.

However, it is an unstable joint because of the range of motion allowed.

It is easily subject to injury because the ball of the upper arm is larger than the shoulder socket that holds it.

To remain stable, the shoulder must be anchored by its muscles, tendons, and ligaments.

Some shoulder problems arise from the disruption of these soft tissues as a result of injury or from overuse or underuse of the shoulder. Other problems arise from a degenerative process in which tissues break down and no longer function well.

Shoulder pain may be localized or may be referred to areas around the shoulder or down the arm. Disease within the body (such as gallbladder, liver, or heart disease, or disease of the cervical spine of the neck) also may generate pain that travels along nerves to the shoulder.

Conversely, pain felt in the region of the shoulder blade or scapula nearly always has its origin in the neck.

Dislocation

The shoulder joint is the most frequently dislocated major joint of the body. In a typical case of a dislocated shoulder, a strong force that pulls the shoulder outward (abduction) or extreme rotation of the joint pops the ball of the humerus out of the shoulder socket.

Dislocation commonly occurs when there is a backward pull on the arm that either catches the muscles unprepared to resist or overwhelms the muscles. When a shoulder dislocates frequently, the condition is referred to as shoulder instability.

Fracture

A bone fracture of the shoulder involves a partial or total crack through one of the three bones in the shoulder, the clavicle, the scapula, and the humerus.

The break in a bone usually occurs as a result of an impact injury, such as a fall or blow to the shoulder. Fractures usually involve the clavicle or the neck (area below the ball) of the humerus.