A SLAP injury of the shoulder refers to a tear of the labrum around the rim of the acetabulum (shoulder socket). The labrum is a ring of cartilage around the shoulder socket. It helps support and hold the round head of the humerus (upper arm bone) in the very shallow socket.
The superior labrum is located along the top of the socket. It is attached loosely by elastic connective tissue. A force or load through the shoulder that is greater than the tensile strength of the thick connective tissue can cause tearing of the structures.
There are four types of SLAP lesions. The groups are based on severity. Type 1 occurs most often in older adults. Fraying and thinning of the labrum is most common with this type of SLAP lesion. If surgery is called for, the surgeon will shave off any fragments and smooth the remaining edges of the labrum.
The other types describe the extent of injury. For example, in a type 2 SLAP injury, the biceps anchor where the labrum attached is detached. There may be some frayed edges of the labrum as well.
Type 3 is a bucket-handle shaped tear in the labrum but the biceps anchor is not disturbed. Type 4 has a similar bucket-handle shape that extends all the way into the biceps tendon. Sometimes people have more than one type of tear at a time. Surgery is often needed to repair the more severe injuries.