A labral tear is a common cause of shoulder pain and instability. If your labral tear involves the superior labrum, it is called a SLAP tear, or superior labrum anterior or posterior tear.
Your shoulder joint is composed of a ball and socket structure with a cartilage lining. The lining of the socket is the labrum.
The labrum can tear or detach due to acute injury or overuse. Something as simple as a seatbelt or other form of shoulder harness can cause acute injury to the shoulder, resulting in a labral tear. Likewise, falling onto an extended arm can lead to this type of shoulder injury.
Since SLAP tears can be traumatic and degenerative in nature, they are frequently caused by repetitive forces. Athletes throwing balls overhead, such as a quarterback or pitcher, create a prime example of the repetitive motion that can cause a SLAP tear.