In vertebrate anatomy, the hip, or coxaLatin coxa was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) (: coxae) in medical terminology, refers to either an anatomical region or a joint on the outer (lateral) side of the pelvis.
The hip region is located lateral and anterior to the Buttocks, inferior to the iliac crest, and lateral to the obturator foramen, with and overlying the greater trochanter of the femur. In adults, the three pelvic bones (ilium, ischium and pubis) have fused into one hip bone, which forms the superomedial/deep wall of the hip region.
The hip joint, scientifically referred to as the acetabulofemoral joint ( art. coxae), is the ball-and-socket joint between the pelvic acetabulum and the femoral head. Its primary function is to weight-bearing 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 tilt.
Hip pain may be the result of numerous causes, including nervous, osteoarthritic, infectious, traumatic, and genetic.
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. Thieme Atlas of Anatomy (2006), p 381
The cuplike acetabulum forms at the union of three pelvic bones — the ilium, pubis, and ischium.Faller (2004), pp 174-175 The Y-shaped growth plate that separates them, the triradiate cartilage, is fused definitively at ages 14–16. Thieme Atlas of Anatomy (2006), p 365 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. Thieme Atlas of Anatomy (2006), p 378 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. The centre of the acetabulum (fovea) does not articulate to anything. Instead, it is lined with fat pad and attached to ligamentum teres. The acetabular labrum is horse-shoe shaped. Its inferior notch is bridged by transverse acetabular ligament. 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.
The acetabulum is oriented inferiorly, laterally and anteriorly, while the femoral neck is directed superiorly, medially, and slightly anteriorly.
The sagittal angle of the acetabular inlet is an angle between a line passing from the anterior to the posterior acetabular rim and the sagittal plane. It measures 7° at birth and increases to 17° in adults.
Wiberg's centre-edge angle (CE angle) is an angle between a vertical line and a line from the centre of the femoral head to the most lateral part of the acetabulum, Page 131 in: as seen on an anteroposterior radiograph.[3]
The vertical-centre-anterior margin angle (VCA) is an angle formed from a vertical line (V) and a line from the centre of the femoral head (C) and the anterior (A) edge of the dense shadow of the subchondral bone slightly posterior to the anterior edge of the acetabulum, with the radiograph being taken from the false angle, that is, a lateral view rotated 25 degrees towards becoming frontal.
The articular cartilage angle (AC angle, also called acetabular index Page 309 in:
An abnormally small angle is known as coxa vara and an abnormally large angle as coxa valga. Because changes in shape of the femur naturally affects the knee, coxa valga is often combined with genu varum (bow-leggedness), while coxa vara leads to genu valgum (knock-knees).
Changes in the CCD angle is the result of changes in the stress patterns applied to the hip joint. Such changes, caused for example by a dislocation, change the patterns inside the bones. 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.
The strong but loose fibrous capsule of the hip joint permits the hip joint to have the second largest range of movement (second only to the shoulder) and yet support the weight of the body, arms and head.
The capsule has two sets of fibers: longitudinal and circular.
The extracapsular ligaments are the iliofemoral, ischiofemoral, and pubofemoral ligaments attached to the bones of the pelvis (the ilium, ischium, and pubis respectively). All three strengthen the capsule and prevent an excessive range of movement in the joint. Of these, the Y-shaped and twisted iliofemoral ligament is the strongest ligament in the human body. It has a tensile strength of 350 kg. Iliofemoral ligament is a thickening of the anterior capsule extending from anterior inferior iliac spine to intertrochanteric line. Ischiofemoral ligament is the thickening of posterior capsule of the hip and pubofemoral ligament is the thickening of the inferior capsule. In the upright position, iliofemoral ligament prevents the trunk from falling backward without the need for muscular activity, thus preventing excessive hyperextension. In the sitting position, it becomes relaxed, thus permitting the pelvis to tilt backward into its sitting position. Ischiofemoral prevents excessive extension and the pubofemoral ligament prevents excess abduction and extension.
The zona orbicularis, which lies like a collar around the most narrow part of the femur neck, is covered by the other ligaments which partly radiate into it. The zona orbicularis acts like a buttonhole on the femoral head and assists in maintaining the contact in the joint.
All three ligaments become taut when the joint is extended - this stabilises the joint, and reduces the energy demand of muscles when standing. teachmeanatomy.net . teachmeanatomy.net. Retrieved on 2013-07-12.
The intracapsular ligament, the ligamentum teres, is attached to a depression in the acetabulum (the acetabular notch) and a depression on the femoral head (the fovea of the head). It is only stretched when the hip is dislocated, and may then prevent further displacement.
It is not that important as a ligament but can often be vitally important as a conduit of a small artery to the head of the femur, that is, the . Hip Fracture in Emergency Medicine at Medscape. Author: Moira Davenport. Updated: Apr 2, 2012 This artery is not present in everyone but can become the only blood supply to the bone in the head of the femur when the neck of the femur is fractured or disrupted by injury in childhood. Thieme Atlas of Anatomy (2006), pp 383, 440
The hip has two anatomically important Anastomosis, the cruciate and the trochanteric anastomoses, the latter of which provides most of the blood to the head of the femur. These anastomoses exist between the femoral artery or profunda femoris and the gluteal vessels.Clemente (2006), p 227
The movements of the hip joint is thus performed by a series of muscles which are here presented in order of importance with the range of motion from the neutral zero-degree position indicated:
At the 2022 Consumer Electronics Show, a company named Safeware announced an Airbag that is designed to prevent hip fractures among such uses as the elderly and hospital patients.
Abnormal orientation of the acetabular socket as seen in hip dysplasia can lead to hip subluxation (partial dislocation), degeneration of the acetabular labrum. Excessive coverage of femoral head by the acetabulum can lead to pincer-type femoro-acetabular impingement (FAI).
The female hips have long been associated with both fertility and general expression of human sexuality. 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. Similarly, fashion through the ages has often drawn attention to the girth of the wearer's hips.
==Additional images==
Femoral neck angle
Capsule
Ligaments
Blood supply
Muscles and movements
Clinical significance
Sexual dimorphism and cultural significance
See also
Notes
External links
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