Hip facts for kids

Quick facts for kids Hip
Bones of the hip region
Latin	coxa

In vertebrate anatomy, hip (or "coxa" in medical terminology) refers to either an anatomical region or a joint.

The hip region is located lateral and anterior to the gluteal region, inferior to the iliac crest, and overlying the greater trochanter of the femur, or "thigh bone". In adults, three of the bones of the pelvis have fused into the hip bone or acetabulum which forms part of the hip region.

The hip joint, scientifically referred to as the acetabulofemoral joint (art. coxae), is the joint between the femur and acetabulum of the pelvis and its primary function is to support the weight of the body in both static (e.g., standing) and dynamic (e.g., walking or running) postures. The hip joints have very important roles in retaining balance, and for maintaining the pelvic inclination angle.

Pain of the hip may be the result of numerous causes, including nervous, osteoarthritic, infectious, traumatic, and genetic.

Structure

Region

The proximal femur is largely covered by muscles and, as a consequence, the greater trochanter is often the only palpable bony structure in the hip region.

Articulation

Radiograph of a healthy human hip joint

The hip joint is a synovial joint formed by the articulation of the rounded head of the femur and the cup-like acetabulum of the pelvis. It forms the primary connection between the bones of the lower limb and the axial skeleton of the trunk and pelvis. Both joint surfaces are covered with a strong but lubricated layer called articular hyaline cartilage.

The cuplike acetabulum forms at the union of three pelvic bones — the ilium, pubis, and ischium. The Y-shaped growth plate that separates them, the triradiate cartilage, is fused definitively at ages 14–16. It is a special type of spheroidal or ball and socket joint where the roughly spherical femoral head is largely contained within the acetabulum and has an average radius of curvature of 2.5 cm. The acetabulum grasps almost half the femoral ball, a grip augmented by a ring-shaped fibrocartilaginous lip, the acetabular labrum, which extends the joint beyond the equator. The joint space between the femoral head and the superior acetabulum is normally between 2 and 7 mm.

The head of the femur is attached to the shaft by a thin neck region that is often prone to fracture in the elderly, which is mainly due to the degenerative effects of osteoporosis.

Images for kids

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  Hip joint. Lateral view.

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  Hip joint. Lateral view.

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  Muscles of Thigh. Anterior views.

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  Illustration of Hip (Frontal view).

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  X-ray of the hip, with measurements used in X-ray of hip dysplasia in adults.