ILIUM. 85 



sacrum, and gives attachment to the iuferior sacro-iliac ligament. 

 The iliacus muscle is attached to the venter surface. On the 

 lower jDortion is a line or ridge continuous with the anterior edge 

 or brim of the pubis ; together these form the ilio-pectineal line, 

 which inferiorly separates the true pelvis from the false. On the 

 inferior border of the shaft is the nutrient foramen, and in front 

 of the acetabulum a second depression for the inner head of the 

 rectus femoris muscle. Below this depression is the ilio-pectineal 

 eminence, which marks the junction of the ilium and the pubis, 

 and gives attachment to the psoas parvus muscle. The inner 

 part is smooth, concave, and grooved backwards and downwards 

 for the obturator vessels. 



Fig. 20. 



Left postero-lateral view of a Horse's pelvis. 1, Anterior iliac spine ; 2, 

 Posterior iliac spine. The iliac crest is the border joiuing 1 and 2 ; 3, Iliac 

 shaft ; 4. The acetabulum, the large rough ridge above is the sciatic spine ; 

 6, Inferior ischiatic spine, posterior to which is the tuberosity. 



The anterior border, or crest of the ilium, lies above the 

 sacral transverse process. It is concave above, convex below, 

 thin in its middle, a^nd roughened for the attachment of the 

 longissimus dorsi and other muscles. Internally it terminates in 

 a rounded eminence, the 2^osterior iliac spine, which rises above 

 the last lumbar and first sacral spines, and forms the highest 

 part of the croup. Externally and anteriorly it terminates in 

 the anterior iliac spine, which consists of four eminences, two 

 superior and two inferior, supported on a thick, strong, projecting 

 bony plate ; these eminences give attachment to the oblique and 



