What Is a Posterior Lesion?

In general, a posterior lesion is some sort of injury resulting in damage to an area located towards the back, or caudal, section of the body. Specifically, the term posterior lesion is usually used to describe an injury to a particular section of the shoulder positioned towards the back of the body. This type of injury can cause inflammation symptoms including swelling, tenderness, and pain upon moving. Though an injury to the shoulder can result in pain situated exclusively in the back of the shoulder, due to the complex nature of the shoulder joint, a posterior lesion is often the result of problems involving a tear of the labrum causing all-over shoulder symptoms.

The labrum is a sleeve-like section of cartilage, or fibrous tissue that conforms to the dish-shaped joint of the shoulder called the glenoid. This extension of the shoulder joint cradles the humerus, or upper arm bone, and provides a secure attachment of the upper arm to the trunk. This sheath gives the shoulder stability while allowing the arm to move in more ways than most other parts of the body. Injury to the labrum often encompasses both the front and the back of this protective sheath, a condition called a Superior Labral Tear from Anterior to Posterior (SLAP) tear.

A SLAP tear results from damage to the top section of the cartilage. This affects the area where the biceps or anterior upper arm muscles hook into the shoulder complex. This injury often extends to the back or posterior section as well causing an all-over shoulder pain.

Commonly the result of an injury caused by strain of the shoulder with repetitive overhead activities or a fall with the arm in an outstretched position, a posterior lesion of the shoulder can result in a decrease in shoulder stability. It may also cause movement difficulties or dysfunction, and a “cog wheel” effect with attempts at shoulder movement. A cog wheel effect is the sensation of the shoulder skipping or catching during movement, specifically overhead movements with this type of injury to the shoulder.

Treatment of a posterior lesion to the shoulder depends on the severity of the damage. Rest and ice are indicated for the first 24 to 48 hours after injury, with anti-inflammatory medications to manage swelling and inflammation side effects. Physical therapy management involves pain-relieving techniques followed by an exercise and stretching routine to help return pain-free, unrestricted movement of the shoulder. In severe cases, surgery is necessary to repair the damaged cartilage, and restore shoulder stability and movement.