426 A MANUAL OF ANATOMY 



parietal pelvic fascia, levator ani, and pubo-prostatic ligament. 

 The internal surface is oval, and occupies an oblique plane, which 

 is directed downwards and backwards. It is covered by cartilage, 

 and articulates with its fellow to form the symphysis pubis, a plate 

 of fibro-cartilage intervening. 



The borders are external and superior. The external border, 

 which is sharp, looks into the obturator foramen, and gives attach- 

 ment to part of the obturator membrane. The superior border 

 or crest is thick, and about an inch long. At its outer extremity is 

 the pubic spine, which may be blunt or sharp, for the attach- 

 ment of Poupart's ligament, and internally is the puhic angle, 

 which surmounts the internal surface. The crest gives attachment 

 to the conjoined tendon, pyramidalis, and outer head of the rectus 

 abdominis. 



The inferior ramus passes downwards and outwards, and corre- 

 sponds in all respects with the ischial ramus, which it joins. Its 

 anterior surface gives origin, from within outwards, to the gracilis, 

 adductor brevis, adductor magnus, and obturator externus. The 

 structures attached to the posterior surface are portions of the 

 obturator internus and parietal pelvic fascia. 



The superior ramus extends outwards and upwards from the 

 body to the ilio - pectineal eminence and anterior part of the 

 acetabulum, of which latter it forms one-fifth. It lies above the 

 obturator foramen, and is triangular. Superiorly, at the back 

 part, is a prominent ridge, representing the pectineal portion of the 

 ilio -pectineal line, which leads to the pubic spine, and gives attach- 

 ment to the following structures : the pubic lamina of the fascia 

 lata, pectineus, Gimbernat's ligament, and conjoined tendon. 

 In front of this line is the superior or pectineal surface, which is sloped 

 downwards and forwards, and is triangular. It supports the 

 pectineus, and is limited antero-inferiorly by the obturator crest, 

 which extends from the pubic spine to the anterior margin of the 

 cotyloid notch. The inferior surface presents the obturator groove 

 for the obturator vessels and nerve, the direction of which is down- 

 wards, forwards, and inwards. The posterior surface gives partial 

 origin to the obturator internus. 



The acetabulum or cotyloid cavity is situated on the outer surface 

 of the bone, and is directed downwards, outwards, and forwards. 

 It is deep and circular, and articulates with the head of the femur. 

 The ischium forms rather more than two-fifths of it, the ilium 

 rather less, and the os pubis the remaining fifth. It is surmounted 

 by a prominent brim, upon which the cotyloid ligament is set, except 

 at the anterior and inferior part, where there is the cotyloid notch, 

 this being bridged over by the cotyloid and transverse ligaments; 

 The capsular ligament is attached to the bone just outside the brim. 

 The interior is divided into two parts — articular and non- 

 articular. The articular portion is covered by cartilage, which 

 is arranged in the form of a horseshoe, and surrounds the circum- 

 ference, except opposite the cotyloid notch. The non-articular part, 



