B: 
THE ANTERIOR LIMB. 212 
Flexor group. The muscles arise in front of the axis of the 
humerus and are inserted on the radius and ulna in front of the 
elbow-joint. 
(a) 
(b) 
The biceps brachii. Origin: Anterior border of glenoid 
cavity. Insertion: Ventromedial surface of the ulna and 
medial surface of the radius. The muscle possesses only one 
head in the rabbit. 
The brachialis. Origin: Anterior and lateral surfaces of 
the humerus, divided unequally into a larger lateral and a 
smaller medial portion by the insertion tendons of the 
deltoideus and abductores muscles. Insertion: In common 
with the biceps. 
6. Muscles arising from the distal end of the humerus and the 
radius and ulna and inserted on the hand (extensors and flexors of 
the hand and of the individual digits). The long insertion tendons 
pass through perforations of the dorsal carpal and transverse 
(ventral) carpal ligaments (Fig. 75). 
A. 
Extensor group. The muscles have a general area of 
origin from the lateral epicondyle of the humerus and the antero- 
dorsal, or anterolateral surface of the radius and ulna. Insertion 
dorsal. 
’ 
(a) 
(b) 
(c) 
(d) 
The extensor carpi radialis longus. Origin: Lateral 
epicondyle. Insertion: Base of the second metacarpal. 
The extensor carpi radialis brevis. Origin: Lateral 
epicondyle. Insertion: Base of the third metacarpal. 
The muscle is partly fused with the foregoing one, and the 
tendons are closely associated on the wrist 
The abductor pollicis. Origin: Anterolateral surface of 
the radius and ulna. Insertion: Base of the first meta- 
carpal. The muscle is partly concealed by (e). Its tendon 
forms a conspicuous cross with those of (a) and (b). © 
The extensor pollicis et indicis. Origin: Anterolateral 
surface of the radius and ulna. Insertion: Ungual phalanx 
of the pollex and the head of the second metacarpal. Its 
tendon is the first of five in the centre of the carpus. 
The extensor digitorum communis. Origin: Lateral 
epicondyle and proximal end of the ulna. Insertion: By 
four tendons on all phalanges of the four lateral digits. 
