The body of the ischium enters into and constitutes a little more than two-fifths of the acetabulum

Acetabulum

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.-Structure:...

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Surfaces

Its external surface forms part of the lunate surface of the acetabulum and a portion of the acetabular fossa

Acetabular fossa

The acetabular fossa is a fossa located at the centre of the acetabulum. It is occupied by the ligament of head of femur....

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Its internal surface is part of the wall of the lesser pelvis

Lesser pelvis

The lesser pelvis is that part of the space enclosed by the skeleton of the pelvis which is situated between the pelvic inlet and the pelvic floor. Some authors call this cavity the pelvic cavity...

; it gives origin to some fibers of the Obturator internus.

Borders

Its anterior border projects as the posterior obturator tubercle.

From its posterior border there extends backward a thin and pointed triangular eminence, the ischial spine

Ischial spine

From the posterior border of the body of the Ischium there extends backward a thin and pointed triangular eminence, the ischial spine, more or less elongated in different subjects.It can serve as a landmark in pudendal anesthesia.-Surfaces:...

, more or less elongated in different subjects.

Above and below the spine

Above the spine is a large notch, the greater sciatic notch

Greater sciatic notch

Above the ischial spine is a large notch, the greater sciatic notch, converted into a foramen by the sacrospinous ligament.It transmits the Piriformis, the superior and inferior gluteal vessels and nerves, the sciatic and posterior femoral cutaneous nerves, the internal pudendal vessels, and the...

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Below the spine is a smaller notch, the lesser sciatic notch

Lesser sciatic notch

Below the ischial spine is a smaller notch, the lesser sciatic notch; it is smooth, coated in the recent state with cartilage, the surface of which presents two or three ridges corresponding to the subdivisions of the tendon of the Obturator internus, which winds over it.It is converted into a...

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