The posterior border is thick and rough. It slopes medially and forward 
to meet the border of the other side, forming with it the ischial arch (Arcus 
ischiadicus). 
The medial border meets the opposite bone at the symphysis ischii. 
The lateral border is thick and rounded, but concave in its length; it forms 
the lesser sciatic notch (Incisura ischiadica minor), the lower boundary of the lesser 
sciatic foramen. 
The antero-medial angle or symphyseal branch (Ramus symphyseos) 
Crest of ilium 
108 THE SKELETON OF THE HORSE 
Tuber sacrale 
| 
Tuber \ 
core Grooves for ilio- 
ee nee Lae vessels 
of tlium Grooves Jor 
Ler iliaco-femoral 
Nutrient vessels 
foramen 
Depression for 
medial tendon 
of rectus 
femoris 
Obturator foramen 
Fic. 87.—Ossa Coxarum or Mare; VENTRAL VIEW. | 
A, Wing, A’, shaft of ilium; B, acetabular branch, B’, svymphyseal branch, of pubis; C, body, C’, acetabular 
branch (shaft), C”, symphyseal branch, of ischium; 1, auricular surface; 2, ilio-pectineal line; 2’, psoas tubercle; 3, 
arcuate line; 4, articular part, 5, iliae part, of pelvie surface of ilium; 6, ilio-pectineal eminence; 7, pubic tubercle; 8, 
acetabular fossa; 9, articular surface of acetabulum (facies lunata); 10, symphysis pelvis; 11, pubic groove. Dotted 
lines indicate primitive division of os cox. 
meets the pubis, with which it forms the medial boundary of the obturator 
foramen. 
The antero-lateral angle or acetabular branch (Ramus acetabularis) joins the 
other two bones at the acetabulum, of which it forms more than half. Dorsally 
it bears part of the ischiatic spine (Spina ischiadica), and medially it is grooved for 
the obturator vessels. The term shaft is often applied to the constricted part of 
the acetabular branch. 
The postero-medial angle joins its fellow at the symphysis. 
The postero-lateral angle is a thick, three-sided mass, the tuber ischii (Tuber 
ischiadicum); its lower border is the ventral ischiatic spine, to which the biceps | 
femoris and semitendinosus muscles are attached. 
