The acetabulum is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint. There are three bones of the os coxae (hip bone) that come together to form the acetabulum. Contributing a little more than two-fifths of the structure is the ischium, which provides lower and side boundaries to the acetabulum. The ilium forms the upper boundary, providing a little less than two-fifths of the structure of the acetabulum. The rest is formed by the pubis, near the midline. It is bounded by a prominent uneven rim, which is thick and strong above, and serves for the attachment of the acetabular labrum, which reduces its opening, and deepens the surface for formation of the hip joint. At the lower part of the acetabulum is the acetabular notch, which is continuous with a circular depression, the acetabular fossa, at the bottom of the cavity of the acetabulum. The rest of the acetabulum is formed by a curved, crescent-moon shaped surface, the lunate surface, where the joint is made with the head of the femur. Its counterpart in the pectoral girdle is the glenoid fossa.[WP,unvetted]. [ ]

Synonyms: acetabulum acetabular region

This is just here as a test because I lose it

Term information

database cross reference

uberon_slim, pheno_slim

depicted by

external definition

Cavity for the articulation of the proximal bone of the hind limb.[AAO]

external ontology notes

whilst WP defines this as a surface, MA treats it as a bone. There are other FMA classes that may be better suited to representing the surface.

homology notes

During the transformation from the osteolepiform fins to tetrapod limbs, the appendages and girdles underwent a number of radical changes. The pelvic girdle became a weight-bearing structure by evolution of an ischium, a full mesio-ventral contact between the two sides of the girdle, an ilium, and a contact between the vertebral column and the girdle through a sacral rib. Fore- and hindlimbs shifted laterally by reorientation of the glenoid and the acetabulum.[well established][VHOG]



taxon notes

In reptiles and in birds, the acetabula are deep sockets.