102 
ANATOMY OF THE HORSE- 
FORE EXTREMITY. 
The shoulder-joint* is formed between the head of the 
humerus and the glenoid cavity of the scapula: their adaptation 
(as dried bones) appears incomplete, in consequence of the com¬ 
paratively disproportionate magnitude of the ball to the socket : 
this is in some degree compensated for, however, by the project¬ 
ing border of the cartilage with which the glenoid cavity is lined. 
The bones are maintained in apposition by— The capsular mem¬ 
brane, which is found very loose when denuded of the surround¬ 
ing adherent muscles, bagging about the bones, in order that it 
may not, in the least, restrain their freedom of motion : it is in¬ 
serted around the rough margin of the glenoid cavity, and around 
the neck of the humerus. Its internal surface is synovial; its 
exterior is clothed by firmly adherent muscles, to which the chief 
strength of the articulation is owing; viz. its outer and anterior 
parts by the antea and postea spinati ; its inner and posterior 
parts by the subscapularis and teres minor. 
The elbow-joint* is constituted of the condyles of the hu¬ 
merus moving in the concavities upon the superior extremity of 
the arm-bone, the surfaces of which are covered by cartilage. 
The joint is maintained by—1st, The capsular membrane , which * 
is thin, infixed around the condyles, including their cartilaginous 
surfaces and the hollow behind them, and around the edges of 
the articulatory parts of the arm-bone; also to the olecranon pro¬ 
cess, to the lateral ligaments, and to the tendinous roots of the 
flexor muscles of the leg. 2d, The lateral ligaments. 
The internal , implanted above, into a depression in the side of 
the internal condyle of the humerus, and below, where it becomes 
bifid, into the border of the inner articular cavity of the radial 
portion of the bone, and also into the body of the bone, about 
three inches below the first insertion. The external , shorter and 
stronger, runs from a similar depression on the external condyle 
to a tubercle on the upper and outer part of the radial b^ne.—In 
the young subject, the ulnar portion of the arm-bone is united 
to the radial by a fibro-cartilage; but this gradually undergoes 
conversion into bone as the adult period approaches. 
Knee-joint. —This includes four distinct articulations : one 
between the arm-bone and the upper row of the carpal bones ; 
a second, between the upper and under rows of the carpal bones 
themselves ; a third, between the under row and the three meta¬ 
carpal bones; a fourth, situated posteriorly, between the trape- 
* These well-understood and familiar appellations are preserved in pre¬ 
ference to the adoption of those of a new nomenclature, viz., scapulo-hutne- 
ral, huntero-brachial , See. articulations. 
