ANATOMY. .' 9 



facet for articulation with the sacrum. The anterior 

 border or crest is concave ; the external has a medullary 

 foramen and vascular grooves ; the internal forms the 

 great sciatic notch. The external angle or point of 

 the hip has four tuberosities for muscular attachment. 

 The internal, or antero-internal angle is a rough 

 tuberosity curving upwards and backwards, forming, 

 with the corresponding portion of the opposite ilium, 

 the summit of the croup. The posterior or cotyloid 

 angle offers a facet for the cotyloid cavity, the supra- 

 cotyloid crest, the ilio-pectineal eminence, and some 

 muscular imprints. 



The ischium is the most posterior of the three 

 bones. It is flat and irregularly quadrilateral in shape, 

 and is composed of. a solid portion (the body) and a 

 narrow part (the neck). It is divided into two faces, 

 four borders, and four angles. The upper face is 

 smooth, and forms the floor of the pelvic cavity ; the 

 inferior face is roughened for the attachment of 

 muscles, and presents the ischial crest. The anterior 

 border forms the obturator foramen, the external the 

 small sciatic notch ; the posterior forms the ischial 

 arch, while the internal is articular. The antero^ 

 external or cotyloid angle presents a diarthrodial facet,; 

 and the posterior extremity of the supra-cotyloid crest ;, 

 the antero-internal angle is articulated with the pubis ;. 

 the postero-external forms the ischial tuberosity ; and 

 the postero-internal articulates with that of the 



opposite side. 



The pubis is the smallest of the three bones, and is 

 situated between the ilium and ischium. It is divided 



