The acetabular labrum (glenoidal labrum of the hip joint or cotyloid ligament in older texts) is a fibrocartilaginous ring[1][2][3] which surrounds the circumference of the acetabulum of the hip, deepening the acetabulum.

The labrum is attached onto the bony rim and transverse acetabular ligament.

It is triangular in cross-section (with the apex represented by the free margin).

[2][3] The labrum contributes to the articular surface of the joint[2][1] (increasing it by almost 10%[1]).

[2] The labrum is about 2 to 3 mm thick but is wider and thinner in the anterior portion.