What is a SLAP tear?
The labrum is soft tissue that rims the bony floor of the shoulder socket. SLAP stands for Superior Labrum Anterior Posterior. This refers to the labrum in the upper (superior) region of the shoulder socket. It includes the labrum in the front (anterior) and the back (posterior) of the region. Hence, the acronym for the region:Superior Labrum Anterior Posterior.
What is the function of the SLAP region?
The labrum is tissue that rims the bony floor of the socket (glenoid). It is a soft type of cartilage deepens the socket. This helps keep the shoulder ball in the socket. This increased stability is very important for normal function of the shoulder. A tendon from the biceps attaches to the top of the labrum and tensions the labrum. This increases the stability provided from the labrum. This is important for stabilizing the shoulder when the arm is at shoulder level or higher. The biceps tendon can be injured with the labrum or by itself.
How do you know if you have a SLAP injury?
The most common symptom is pain with overhead activities. Sometimes patients report “clunking” in the shoulder with activities. But neither is very specific. MRI
has proven to be unreliable for identifying SLAP tears. The most important part of diagnosing a SLAP injury is the examination from a shoulder specialist. The second most important part of diagnosing a SLAP injury is an intra-articular injection with Lidocaine. The injection confirms that the pain is coming from the SLAP injury.
Special Case : SLAP tear with a paralabral cyst :
A cyst can form from the joint fluid that leaks out of the joint from a SLAP tear. It can push the thin capsule into a balloon like cyst. These can be quite large.
Sometimes they are big enough that they push into the muscle and cause pain. If they are large enough, they can even push onto the suprascapular nerve and cause weakness in the external rotators of the rotator cuff. The treatment for cysts that are causing symptoms or weakness is surgical, involving treatment of the SLAP and often a drainage or removal of the cyst.