: coxae) in medical terminology, refers to either an anatomical region or a joint on the outer (lateral) side of the pelvis.

Its primary function is to support the weight of the torso 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.

[3] 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.

[7] 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.

[9] 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.

[10] The acetabulum grasps almost half the femoral ball, a grip deepened by a ring-shaped fibrocartilaginous lip, the acetabular labrum, which extends the joint beyond the equator.

[11] 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.

Two continuous trabecular systems emerging on the auricular surface of the sacroiliac joint meander and criss-cross each other down through the hip bone, the femoral head, neck, and shaft.

On the lateral side of the hip joint the fascia lata is strengthened to form the iliotibial tract which functions as a tension band and reduces the bending loads on the proximal part of the femur.

Posteriorly, it is attached to a junction between medial two-thirds and lateral one-third of the femoral neck,[7] one finger breadth away from the intertrochanteric crest.

[30] The hip muscles act on three mutually perpendicular main axes, all of which pass through the center of the femoral head, resulting in three degrees of freedom and three pair of principal directions: Flexion and extension around a transverse axis (left-right); lateral rotation and medial rotation around a longitudinal axis (along the thigh); and abduction and adduction around a sagittal axis (forward-backward);[31] and a combination of these movements (i.e. circumduction, a compound movement in which the leg describes the surface of an irregular cone).

At the 2022 Consumer Electronics Show, a company named Safeware announced an airbag belt that is designed to prevent hip fractures among such uses as the elderly and hospital patients.

[35] The femora are also more widely spaced in females, so as to widen the opening in the hip bone and thus facilitate childbirth.

Since broad hips facilitate childbirth and also serve as an anatomical cue of sexual maturity, they have been seen as an attractive trait for women for thousands of years.

Many of the classical poses women take when sculpted, painted or photographed, such as the Grande Odalisque, serve to emphasize the prominence of their hips.