Ĭhanges in the CCD angle is the result of changes in the stress patterns applied to the hip joint. Coxa valga leads to more compression trabeculae, coxa vara to more tension trabeculae. Ĭhanges in trabecular patterns due to altered CCD angle. 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). Īn abnormally small angle is known as coxa vara and an abnormally large angle as coxa valga. The angle between the longitudinal axes of the femoral neck and shaft, called the caput-collum-diaphyseal angle or CCD angle, normally measures approximately 150° in newborn and 126° in adults ( coxa norma). Suggested cutoff values to classify the angle as abnormally increased include: In normal hips in children aged between 11 and 24 months, it has been estimated to be on average 20°, ranging between 18° to 25°. The articular cartilage angle (AC angle, also called acetabular index or Hilgenreiner angle) is an angle formed parallel to the weight bearing dome, that is, the acetabular sourcil or 'roof', and the horizontal plane, or a line connecting the corner of the triangular cartilage and the lateral acetabular rim. 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. 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, as seen on an anteroposterior radiograph. It measures 7° at birth and increases to 17° in adults. 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. In adults the angle can vary from 33 to 38 degrees. The angle measures 35 degrees at birth, 25 degrees at one year of age, and less than 10 degrees by 15 years of age. The acetabulum is oriented inferiorly, laterally and anteriorly, while the femoral neck is directed superiorly, medially, and slightly anteriorly.Īcetabular angle (or Sharp's angle) is the angle between the horizontal line passing through the inferior aspects of triradiate cartilages ( Hilgenreiner's line) and another line passing through the inferior angle of triradiate cartilage to superior acetabular rim. Transverse and sagittal angles of acetabular inlet plane. 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 joint space between the femoral head and the superior acetabulum is normally between 2 and 7 mm.

Its inferior notch is bridged by transverse acetabular ligament. The acetabular labrum is horse-shoe shaped. Instead, it is lined with fat pad and attached to ligamentum teres. The centre of the acetabulum (fovea) does not articulate to anything. 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. 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 Y-shaped growth plate that separates them, the triradiate cartilage, is fused definitively at ages 14–16. The cuplike acetabulum forms at the union of three pelvic bones - the ilium, pubis, and ischium. Both joint surfaces are covered with a strong but lubricated layer called articular hyaline cartilage. It forms the primary connection between the bones of the lower limb and the axial skeleton of the trunk and pelvis. The socket is also turned such that the outer edge of its roof is more lateral than outer edge of the floor. The socket of the acetabulum is pointing downwards and anterolaterally. The hip joint is a ball and socket synovial joint formed by the articulation of the rounded head of the femur and the cup-like acetabulum of the pelvis.

Complete anatomy of hip joint