The hip is that portion of the body joining the lower extremity to the trunk. It differs in construction from the shoulder, because it is designed for strength as well as mobility; hence it is that the bones are heavier, stronger, with their processes more marked, and that the muscles also are bigger and more powerful. It is often the seat of injury and disease, the bones being fractured, the joint luxated, and frequently affected with tuberculosis and other diseases.

Bones Of The Hip

The bones of the hip are the innominate bone and femur. The innominate bone has its shape determined by its relation to the trunk, being adapted to support and protect the viscera, while the femur has its shape determined by its relation to the extremity, being in the nature of a pole to support it.

The innominate bone (Figs. 500 and 501) is composed of the ilium, ischium, and pubis. These are united in the acetabulum by the triangular cartilage and become ossified about the sixteenth year. The ilium has a crest which serves for the attachment of the transverse abdominal muscles. At its anterior extremity is the anterior superior spine, and at its posterior extremity the posterior superior spine. Its large flat portion, called the a/a, gives origin from both its inner and outer sides to muscles running to the thigh below. The glutei muscles are attached to its outer surface and the iliacus to its inner. Immediately below the anterior superior spine is the anterior inferior spine; to it is attached the rectus femoris tendon. The ischium is below and behind the acetabulum; its tuberosity gives attachment to the hamstring muscles - biceps (outer), semitendinosus, and semimembranosus (inner). Along the inner surface of the ramus of the ischium, in a fibrous canal (Alcock's), run the internal pudic vessels and nerve on their way to the perineum. They lie 4 cm. (1 1/2 in.) from the surface. The pubis lies below and anterior to the acetabulum. Its upper inner edge forms the iliopectineal line, which is continued back to form the brim of the true pelvis. The superior or horizontal ramus goes to the ilium, while its inferior or descending ramus goes to the ischium. The upper surface of the superior ramus gives origin to the pectineus muscle; it is over this muscle that femoral hernia descends. The symphysis pubis is the junction of the two pubic bones in the median line. The crest is the upper anterior edge and gives attachment to the rectus and pyramidal muscles (for muscular attachments see Figs. 438 and 439, page 432). The outer extremity of the crest is the spine of the pubis. To it is attached the inner extremity of Poupart's ligament. The obturator foramen, if the body is in an upright position, is just below and a little anterior to the acetabulum; it is closed by a membrane which is incomplete above to give passage to the obturator vessels and nerve. The outer surface of the membrane gives origin to the obturator externus muscle and the inner surface to the obturator internus. This latter passes out of the pelvis through the lesser sacrosciatic notch just below the spine of the ischium. Through the greater sacro-sciatic notch, above the spine, comes the pyriformis muscle and great sciatic nerve. The acetabulum is located at the junction of the ilium, ischium, and pubis, and lies a little to the outer side of the middle of Poupart's ligament, with the femoral artery passing nearer its inner than its outer edge. The obturator foramen is below and a little anterior to the acetabulum when the body is upright and more anterior when it is horizontal. The bottom of the acetabulum has a large fossa, to the upper portion of which is attached the ligamentum teres, while the lower portion contains a pad of fat. This fossa opens by a large notch, called the cotyloid notch, on the side toward the obturator foramen; therefore the bony socket is incomplete at this point.

Fig. 500.   The innominate bone, viewed from the outside.

Fig. 500. - The innominate bone, viewed from the outside.

Fig. 501.   The innominate bone, viewed from the inside.

Fig. 501. - The innominate bone, viewed from the inside.

Fig. 502.   Innominate bone, resting on its inner side, to show the wedge shaped formation of its outer sur. face. The apex of the wedge is Nelaton's line, running from the anterior superior spine to the tuberosity of the ischium; the anterior plane inclines downward and forward toward the pubis and the posterior plane inclines downward and backward on the ilium.

Fig. 502. - Innominate bone, resting on its inner side, to show the wedge-shaped formation of its outer sur. face. The apex of the wedge is Nelaton's line, running from the anterior superior spine to the tuberosity of the ischium; the anterior plane inclines downward and forward toward the pubis and the posterior plane inclines downward and backward on the ilium.

Fig. 503.   Anterior view of the upper end of the femur with muscular attachments.

Fig. 503. - Anterior view of the upper end of the femur with muscular attachments.

O. H. Allis has pointed out that a line passing from the anterior superior spine to the tuberosity, called the Roser-Nelaton line, forms the apex of a wedge, the ilium sloping down on one side while the ischium and pubes pass down the other. It divides the innominate bone into two parts, an anterior plane and a posterior plane (Fig. 502).

The femur has its neck coming off from the shaft at an upward angle of about 127 degrees (125 degrees to 130 degrees). The head and neck do not lie in the same transverse plane as the line joining the two condyles, but are inclined slightly forward (about 12 degrees). Therefore the neck passes upward, inward, and a little forward. As the result of deformities or disease, the inclination of the neck to the shaft may be reduced, being 90 degrees or less. This condition is known as coxa vara. It may be increased, constituting coxa valga. The articular surface of the head forms slightly more than a hemisphere and has a pit below and posterior to its centre for the attachment of the ligamentum teres. At the outer upper extremity of the neck where it joins the shaft is the greater trochanter. Its tip or most prominent point is toward its posterior surface and is just about opposite the centre of the hip-joint. Downward and inward from the greater trochanter, on the inner and posterior surface of the shaft, is the lesser trochanter. Between the trochanters anteriorly and posteriorly run the intertrochanteric lines. The great trochanter and the part immediately below and posterior gives attachment to the three glutei muscles, the short rotators (Fig. 504), the pyriformis, the obturators, internus with its two gemelli and externus, and the quadratus femoris. The lesser trochanter gives attachment anteriorly to the psoas and the iliacus and immediately below to the pectineus.

Fig. 504.   Posterior view of the upper end of the femur with muscular attachments.

Fig. 504. - Posterior view of the upper end of the femur with muscular attachments.

The anterior intertrochanteric line marks the lower attachment of the capsule; the posterior has inserted into it the quadratus femoris muscle.

Fig. 505.   Muscles of the region of the hip.

Fig. 505. - Muscles of the region of the hip.