366 THE HORSE, 
Chauveau has done, in addition to flexion and extension of the shoulder- 
joint, the four movements of abduction, adduction, circumduction, and 
rotation. It would much puzzle that generally accurate anatomist to turn 
the horse’s foot up in front so that its possessor could see the sole ; yet if 
circumduction and adduction were permitted, this could readily be done as 
by the domestic cat or dog in licking the inside of the fore paw. The 
shoulder joint is, in fact, a true hinge (ginglymus) in the horse, ass, cow, 
sheep, and goat, but in the first of these animals it is more especially 
limited in its movements, by the enormously powerful muscles which 
surround the joint, and which are constantly tense, though extremely 
elastic, and giving way to every voluntary movement. It is a beautiful 
provision of nature, to enable the horse to bear the shocks which his 
shoulders have to sustain in coming down from a leap with a great weight 
on his back, and without it he would be rendered comparatively useless 
to man. 
THE ELBOW JOINT, 
OR THE HUMERO-RADIO-ULNAR ARTICULATION.—This joint is formed 
between the lower extremity of the humerus above, and the junction of 
the radius and ulna below. It is a complete hinge, and has no power of 
pronation or supination as in man, consequently there is no necessity for 
the peculiar additional joint between the radius and ulna, observable in 
man and partially in the dog and cat; but the two 
bones are firmly ossified together in the adult, as 
already described at page 337. 
These bones are connected together by three liga- 
ments, two lateral (an internal and an external), a 
capsular ligament, and a synovial capsule. 
The internal lateral ligament arises from a fossa on 
the side of the internal condyle of the humerus ; it 
takes a vertical course, expanding as it descends: 
and is inserted partly on the roughened inner border 
of the articular cavity of the radius. Its middle 
fibres, which are the longest, take the same course 
as the former, assuming while passing over the radius 
the shape of a cord, which is inserted into the inner 
and fore part of the radius about three inches below 
the former insertion. 
Lhe external lateral ligament is shorter but stronger 
than the internal. It arises from the superior fossa 
and ridge surrounding it, on the outer surface of the 
external condyle of the humerus, and is inserted 
— 4 . . 
Pra. Oe esenor WE into the tuberosity on the upper and external part 
of the radius. Its superficial fibres take a ver- 
merus. tical course, whilst its internal fibres take an 
A. Inferior third of the hu- 
: Bea andinternal oblique direction, from top to bottom and from back 
Cc. Diageo process of to front. 
ulna. . ° . . 
D. Radius. The capsular ligament is attached by its superior 
1. External lateral liga- order to the surfaces surrounding the condyles of 
2. Internal lateral ligament the humerus ; by its inferior border, to the circum- 
3. 3. Fibro - cartilaginous E ae Sere , 
substance uniting the ference of the superior part of the radius ; and by 
ulna to the radius. — jts posterior border to the circumference of the arti- 
cular surface of the ulna. 
The synovial membrane is short anteriorly, very extended, and api 
