A SLAP tear or SLAP lesion is an injury to the glenoid labrum (fibrocartilaginous rim attached around the margin of the glenoid cavity in the shoulder blade). SLAP is an acronym for "superior labral tear from anterior to posterior". Symptoms Several symptoms are common but not specific: Dull, throbbing, ache in the joint which can be brought on by very strenuous exertion or simple household chores. Difficulty sleeping due to shoulder discomfort. The SLAP lesion decreases the stability of the joint which, when combined with lying in bed, causes the shoulder to drop. For an athlete involved in a throwing sport such as baseball, pain and a catching feeling are prevalent. Throwing athletes may also complain of a loss of strength or significant decreased velocity in throwing. Any applied force overhead or pushing directly into the shoulder can result in impingement and catching sensations. Anatomical mechanism The shoulder joint is a "ball-and-socket" joint. However, the 'socket' (the glenoid fossa of the scapula) is small, covering at most only a third of the 'ball' (the head of the humerus). It is deepened by a circumferential rim of fibrocartilage, the glenoidal labrum. Previously there was debate as to whether the labrum was fibrocartilaginous as opposed to hyaline cartilage found in the remainder of the glenoid fossa. Previously, it was considered a redundant, evolutionary remnant, but is now considered integral to shoulder stability. Most agree that the proximal tendon of the long head of the biceps brachii muscle becomes fibrocartilaginous prior to attaching to the superior aspect of the glenoid. The long head of the triceps brachii inserts inferiorly, similarly. Together, all of those cartilaginous extensions are termed the 'glenoid labrum'. A SLAP tear or lesion occurs when there is damage to the superior (uppermost) area of the labrum. These lesions have come into public awareness because of their frequency in athletes involved in overhead and throwing activities in turn relating to relatively recent description of labral injuries in throwing athletes, and initial definitions of the 4 (major) SLAP sub-types, all happening since the 1990s. The identification and treatment of these injuries continues to evolve. Diagnosis Sub-types Twelve varieties of SLAP lesion have been described, with initial diagnosis by MRI or arthrography and confirmation by direct arthroscopy. Type I - 11 o'clock to 1 o'clock. Fraying of the superior labrum, though it remains firmly attached to the glenoid rim. Type II - 11