THE SCAPULA. 335 
THE Foss# are two externally, (a) the anterior, and () the posterior 
fossa, divided by the spine (1). These lodge and give attachment to the 
tibres of the supra and infra-spinatus muscles, while the internal fossa, 
sometimes called the venter scapule (belly of the scapula), in the same 
way subserves the use of the subscapularis. 
THE SUPERIOR BORDER is rough for the attachment of the broad strip of 
cartilage, which increases the length of the blade. The anterior border 
is thin, while the posterior is comparatively thick. 
THE TWO SUPERIOR ANGLES present nothing very remarkable, but the 
inferior is occupied by the coracoid process anteriorly, and by the glenoid 
cavity posteriorly—which latter is a smooth oval cavity, lined with 
cartilage. It receives the head of the humerus 
Fis, 23.—OuTer Surrace oF Lerr ScaPuLa. 
a. Spine. b. Posterior fossa. : ; 
2. Coracoid process, c. Superior costa, to which the cartilage is 
3. Glenoid cavity. attached. 
. Anterior fossa. 
R 
ON ACCOUNT OF THE IMPORTANT offices belonging to the muscles which 
occupy the fossz on this bone, and since it is found that in proportion to 
the extent of the latter will be the muscular power, horsemen examine 
with great care the due development of the scapula. Unless it is long 
and broad it may always be predicted that the hunter will be powerless 
in using his forelegs “in dirt,” or in getting out of other difficulties ; and 
though some hacks with short shoulders may go well enough, yet, in the 
majority, such will not be the case. Heavy draught-horses, in which a 
great thickness of muscle is heaped upon the blade, are not so dependent 
upon its length and breadth, as has been already shown in treating of the 
external form of the horse at page 92. 
HUMERUS, THE UPPER ARM-BONE, 
Lirs between the scapula and elbow, in an oblique direction from the 
point of the shoulder downwards and backwards. 
LIKE ALL THE LONG BONES, the humerus may be described as consisting 
of a body or shaft and two extremities. 
Tu Bopy, which has a prismatic section, looks as if it had been twisted 
