OSTEOLOGY OF THE HORSE. 61 



Divisiott— 'Into haunch, thigh, hock, leg, pastern, coronet, and 

 foot. 



OF THE HAUNCH. 



The superior part of the haunch is formed by the ihac portion 

 of the OS innominatum ; its middle has for base the os femoris ; 

 below and in front, it is terminated by the patella. 



ROUND BONE. (OS FEMORIS.) 



Form — Long, cylindrical. Magnitude — The strongest and 

 heaviest bone in the body; and oneof tJje longest. Direction — 

 Oblique ; from above downward, and from behind forward. 



Division — Into body and extremities. 



Body. — Upper part, expanded ; flattened, posteriorly ; promi- 

 nent, anteriorly ; and having, projecting from its outer border, a 

 broad, flat, semicircular process, curved forwards, which is the 

 small external trochanter : to it are fixed the faschia lata, tensor 

 vaginai and gluteus externus. Nearly opposite to this, only 

 somewhat higher, the inner border has an asperous oblong promi- 

 nence, the internal trochanter, which receives the insertions of the 

 psoae and pectineus muscles. The lower half of the body is con- 

 tracted, round, and smooth: and on its postero-external part pre- 

 sents a deep oval pit, with asperous surfaces, which give attach- 

 ment to the gastrocnemii. About the middle of the body, be- 

 hind, is the medullary foramen. 



The superior extremity consists of two parts : — a hemis- 

 pherical, smooth, articulatory head, looking upwards and inwards, 

 joined to the body by a thick flattened neck, and exhibiting on its 

 inner side a wide deep fissure, into which is fixed the round liga- 

 ment ; the head itself being adapted to the acetabulum in the 

 OS innominatum. The other portion is a larger irregular projec- 

 tion, rising posteriorly into a pyramidal eminence, at the root of 

 which, behind, is a deep oval cavity : this process, the great 

 external trochanter, presents a broad, uneven, asperous surface 

 outwardly, which receives the implantation of the gluteal muscles ; 

 a waving roughened crest, superiorly, to which are attached the 

 obturator muscles ; and a concave smooth surface inwardly, to 

 which is fixed the capsular ligament. 



The inferior extremity presents for consideration, a 

 trochleal prominence and two condyles. The first, the pulley- 

 like articulatory surface in front, consists of a broad semicircular 

 groove, bounded on either side by a prominence, of which the in- 

 ternal projects much more than the external : over this surface 

 plays the patella. The condyles, most conspicuous posteriorly, 

 much resemble each other, excepting that the external is the 



