Internal Impingement Shoulder

Definition: Internal impingement is a specific type of shoulder injury that is seen primarily in throwing athletes. Internal impingement consists of injury to the following structures:

• The posterior labrum
  The labrum in the posterior-superior region of the shoulder is often frayed or partially torn. In more severe cases, the tear can extend up towards the attachment of the biceps tendon, a so-called SLAP tear.

• The rotator cuff
  The rotator cuff is partially torn on its undersurface. The type of tear is called a partial thickness tear--not a complete tear of the rotator cuff.

The problem is caused from pinching of the tuberosity (top of the humerus) against the labrum. Patients with internal impingement characteristically lack internal rotation--the ability to fully rotate the shoulder inward.