What are the three main parts that fuse to form the hip bone?

The hip bone is formed by the fusion of three bones: the ilium (superior fan-shaped part), the ischium (posteroinferior part for sitting), and the pubis (anteromedial part). They converge at the acetabulum.

What is the acetabulum and what is its function?

The acetabulum is a deep, cup-shaped socket on the lateral side of the hip bone, formed by contributions from the ilium, ischium, and pubis. Its primary function is to articulate with the head of the femur, forming the hip joint.

How can you determine the side (left or right) of an isolated hip bone?

To determine the side, hold it with the acetabulum facing laterally, ensure the obturator foramen is inferior to the acetabulum, and check that the ilium is superior, the pubis anterior, and the ischium posteroinferior.

What is the obturator foramen and what structures pass through it?

The obturator foramen is a large opening formed by the pubis and ischium. It is mostly covered by the obturator membrane, but the obturator canal transmits the obturator nerve and vessels.

What are the key anatomical differences between male and female hip bones?

Sex differences include a wider greater sciatic notch in females, a triangular obturator foramen in females vs. oval in males, and a shallower iliac fossa in females.

What is the ischial tuberosity and why is it important?

The ischial tuberosity is a roughened area on the ischium that bears body weight during sitting. It also provides attachment points for muscles like the hamstrings and adductor magnus.

How does the hip bone ossify during development?

Ossification involves 3 primary centers (ilium, ischium, pubis) appearing in utero and 8 secondary centers appearing at puberty. Fusion typically completes by 20–25 years of age.

Hip Bone (Os Coxae) – Ilium, Ischium & Pubis

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