lO VETERINARY OBSTETRICS. 



into two faces, three borders, and three angles. The 

 superior face is smooth and concave ; the inferior has 

 a large groove for the pubio-femoral ligament. The 

 anterior border is thin and rough, the posterior thick 

 and concave, and assists in forming the obturator 

 foramen ; the internal border is thick and articular. 

 The external or cotyloid angle forms the bottom of the 

 cotyloid cavity ; the internal and posterior angles are 

 articular. 

 ' The sacrttm results from the fusion of five verte- 



brae into a single, voluminous, pyramidal or triangular 

 mass. It may be said to terminate the vertebral spine 

 posteriorly. It encloses the pelvic cavity above, and 

 articulates in front with the last lumbar vertebra, 

 behind with the first coccygeal, and laterally with the 

 ossa innominata. It is divided Into two faces, two 

 borders, a base, an apex, and a central canal. The 

 superior face presents the spinous processes forming 

 the sacral spine, bent backvi^ards and diminishing In 

 length posteriorly; it offers on each side the four 

 supra-sacral foramina. The inferior face is smooth 

 and shows the lines of separation of the vertebrae, and 

 on each side the four sub-sacral foramina. The borders 

 are thick and concave, rough posteriorly, having forward 

 Sl broad, rough auricular surface to articulate with the 

 .ossa innominata. The base offers, on the median line, 

 the anterior orifice of the sacral canal, and the anterior 

 articular head of the body of the first sacral vertebra ; 

 ' on the sides, the articular processes and the anterior 

 notches of that vertebra, and the outside, the two large 

 facets for articulation with the last lumbar vertebra. 



