Acetabulum

From Free net encyclopedia

Template:Infobox Bone The acetabulum is the concave articular surface of the pelvis, formed by the parts of three bones, the ilium, ischium, and pubis. The head of the femur articulates with the pelvis at the acetabulum, forming the hip joint. In reptiles and in birds, the acetabulum are deep sockets. It has its counterpart in the pectoral girdle, namely, glenoid fossa.

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

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Details from Gray's

The Acetabulum (cotyloid cavity).—The acetabulum is a deep, cup-shaped, hemispherical depression, directed downward, lateralward, and forward.

It is formed medially by the pubis, above by the ilium, laterally and below by the ischium; a little less than two-fifths is contributed by the ilium, a little more than two-fifths by the ischium, and the remaining fifth by the pubis.

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 orifice, and deepens the surface for articulation.

It presents below a deep notch, the acetabular notch, which is continuous with a circular non-articular depression, the acetabular fossa, at the bottom of the cavity: this depression is perforated by numerous apertures, and lodges a mass of fat.

The notch is converted into a foramen by the transverse ligament; through the foramen nutrient vessels and nerves enter the joint; the margins of the notch serve for the attachment of the ligamentum teres.

The rest of the acetabulum is formed by a curved articular surface, the lunate surface, for articulation with the head of the femur.

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