Paleontology Wiki
Bone: Acetabulum of pelvis
Illu pelvic girdle.jpg
Pelvic girdle
The Acetabulum
Gray's subject #57 237
MeSH A02.835.232.611.108
Dorlands/Elsevier a_06/12104853

The acetabulum is a concave surface of the pelvis, formed by the parts of three bones. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.


There are three bones in the pelvis which 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 glenoidal labrum (cotyloid ligament), which contracts 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.

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


The word acetabulum means "little vinegar cup", and was the Latin word for a small vessel for storing vinegar (see acetabulum). The word was later also used as a unit of volume, equal to roughly 270 ml.

Additional images

External links

  • SUNY Labs 17:01-0501 - "Major Joints of the Lower Extremity: Hip joint"
  • SUNY Labs 43:os-0407 - "The Female Pelvis: Articulated bones of pelvis"

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.