THE HIP-BONB: 139 



The ilium has two surfaces: the external surface, or dorsum, is convex in its 

 general contour. It is Hmited superiorly by the semicircular crest, and is crossed 

 by the three gluteal ridges. The superior gluteal ridge commences at the crest 

 about 5 cm. (2") from its posterior termination, and passes downwards to the 

 middle of the greater sciatic ( ilio-sciatic) notch. The space included between this 

 ridge and the crest gives origin to the gluteus iiKtximus, and at its lower part to a few 

 fibres of the pyrifonnis. The middle gluteal ridge extends from the crest 2 5 cm. 

 (1") behind its anterior extremity, and passes across the dorsum to terminate near 

 the posterior end of the superior gluteal ridge, at the greater sciatic notch. The 

 surface of bone between this ridge and the crest is for the origin of the gluteus 

 medius. The inferior gluteal ridge begins in the notch separating the anterior 

 iliac spines, and terminates posteriorly in the middle of the greater sciatic notch. 

 The space between the middle and inferior ridges gives origin to the ^/»^msmnm».s, 

 except a small area adjacent to the anterior superior iliac spine for the tensor vagince 

 femorls. The bone between the inferior gluteal ridge and the margin of the acetab- 

 ulum affords attachment to the capsule of the hip-joint. Towards its anterior part 

 there is a rough surface for the reflected tendon of the rectus. 



The internal surface of the ilium consists of an anterior concave portion, termed 

 the iliac fossa ; it lodges the iliacus muscle. The fossa is limited below by the 

 ilio-pectlneal line; this line receives, at its anterior part, the insertion of the psoas 

 parvus. A small portion of the ilium extends below the ilio-pectineal line to meet 

 the ischium. The surface posterior to the fossa is divided into an auricular sur- 

 face for articulation with the lateral aspect of the upper portion of the sacrum, and 

 a superior rough surface — the tuberosity — for the posterior sacro-iliac and ilio- 

 lumbar ligaments. The crest extends from the anterior superior iliac to the pos- 

 terior superior iliac spine. It is thickest at its extremities. The prominent edges, 

 or lips, are for the attachment of muscles and fasciae. 



The outer lip affords attachment to the gluteal portion of the fascia lata. The 

 external oblique is inserted into the anterior half, and the latissimus dorsi arises for about 

 an inch more posteriorly. The anterior two-thirds of the intermediate space gives 

 origin to the internal oblique. The inner lip, by its anterior three-fourths, gives 

 attachment to the transverscdis ; behind this is a small surface for the quadratus lum- 

 borum, and the remainder is occupied by the erector spina'. The extreme inner 

 margin of the lip in the anterior two-thirds serv^es for the attachment of the iliac 

 fascia. 



The anterior border of the ilium extends from the anterior superior spine to 

 the margin of the acetabulum. The anterior superior spine gives attachment to 

 Poupart's ligament, and the sartorius which also arises from the upper half of the 

 superior iliac notch. This notch is terminated inferiorly by the anterior inferior 

 spine ; it is smaller, less prominent than the superior, and gives origin to the 

 straight head of the rectus femoris and the main limb of the ilio-femoral band of 

 the capsule of the hip-joint. Beneath the inferior iliac spine is the inferior iliac 

 notch ; it is broad, but shallow, and limited liy an eminence, the ilio-pubal ridge, 

 which indicates the line of ankylosis of the pubes and the ilium. A few lilires of 

 the iliacus arise from this notch. 



The posterior border of the ilium presents above the posterior superior spine, 

 which gives attachment to the greater sacro-sciatic ligament and the vw It Ifldus spins', 

 and a portion of the oblique sacro-iliac ligament. Below this is a shallow notch 

 terminating below in the posterior inferior spine, corresponding to the posterior 

 border of the auricular surface. This spine receives a portion of the greater sacro- 

 sciatic ligament. Below the spine the posterior border of the ilium forms the upper 

 segment of the greater sciatic notch. 



The ischium consists of a thick solid body, a prominent tuberosity, and a 

 ramus. 



The body is triangular; its outer surface forms the posterior and inferior section 

 of the acetabulum. The inner surface forms part of the true pelvis, and meets the 

 ilium a little distance below the ilio-pectineal line. It also forms the floor, or 

 non-articular portion, of the acetabulum, and meets the pubes anteriorly; the line 

 of junction is frequently indicated in adult bones by a rough line extending from 

 the ilio-pubal ridge to the margin of the obturator foramen. The free border of 



