OSTEOLOr.V OF THE HORSE. 49 



the venter scapulee, and sometimes the subscapular fossa, is 

 smooth, though uneven, being excavated in the middle, flattened 

 laterally and inferiorly, and is marked by the attachment of 

 muscles : in the middle, and principally, by the subscapularis ; 

 around the posterior angle, by the teres major ; superiorly, by the 

 serratus magnus ; still higher, along the border, by the rhom- 

 boidei. 



BouDKKs. — The superior, nearly straight and but little more 

 than half the length of the lateral, is thick, and presents a grooved 

 scabrous summit, into which is fixed the cartilage of the scapula, 

 I'orming a flexible plate of considerable breadth, diminishing in 

 thickness as it ascends from the bone, and terminating in a thin 

 convex edge, which is inclined inward. — The anterior border 

 describes the figure of an inverted S. It is thin, and presents a 

 sharp edge superiorly ; below, it grows obtuse and rounded, and 

 terminates in the coracoid process, a rough hemispherical pro- 

 minence, presenting in front of the shoulder-joint, to which is 

 affixed the coraco-brachialis and flexor brachii. — The posterior 

 border is obtuse, rounded, and smooth, except that, infeiiorly, 

 there are some few unimportant asperities : it affords attachment 

 to the teres minor and large head of the triceps extensor brachii. 



Angles. — The two superior are rectangular and sharp : the 

 postero-superior has, externally, a prominence just below it, mark- 

 ing the origin of the teres major. — The inferior angle is repre- 

 sented, or, rather, has its place supplied, by the glenoid cavity — 

 the smooth ovoid shallow cup, notched inwardly, formed for arti- 

 culation with the head of the os humeri : it is rendered deeper by 

 a marginal cartilage ; and has around its border inequalities and 

 porosities, to which is fixed the capsular ligament. Between the 

 glenoid cavity and the coracoid process, internally, is an excava- 

 tion, serving for a passage to the tendon of the subscapularis. 



Connexion. — The scapula is attached to the thorax by the 

 several nmscles passing between them ; also by two ligamentous 

 fasciae. 



Development. — In the very young subject, the coracoid pro- 

 cess forms an epiphysis : in old age, the cartilage of the scapula 

 takes on ossification. 



HUMERUS. 



Situation. — Between the scapula and the arm ; placed in an 

 oblique but contrary direction to the scapula, viz. downwards 

 and backwards ; whereby an angular space, of considerable 

 extent, is left between the two bones. 



Form. -~Cy\\ndro\d ; presenting the appearance of having been 

 twisted around itself. 



