60 



DISSECTION OF FRONT OF FOREARM. 



boundaries ; 



contents of 

 the space 



and their 

 position to 

 one another 



lymphatic 

 glands. 



Superficial 

 group 

 contains 

 five muscles 



Pronator 



origin 

 by two 

 heads ; 



insertion ; 

 relations ; 



and the outer muscles of the forearm, and is triangular in shape, 

 with the wider part towards the humerus. It is bounded on the 

 outer side by the supinator longus muscle, and on the inner side 

 by the pronator teres. The aponeurosis of the limb is stretched 

 over the space ; and the bones, covered by the brachialis anticus 

 and supinator brevis, form the deep boundary. 



Contents. In the hollow are lodged the termination of the 

 brachial artery, with its veins, and the median nerve ; the musculo- 

 spiral nerve ; the tendon of the biceps muscle ; and small recurrent 

 vessels, with much fat. 



These several parts have the following relative position : The 

 tendon of the biceps is directed towards the outer boundary to 

 reach the radius ; and on the outer side, concealed by the supinator 

 longus muscle, is the musculo-spiral nerve. Nearly in the centre 

 of the space are the brachial vessels and the median nerve, the 

 nerve being internal ; but as the artery is inclined to the outer 

 side of the limb, they soon become distant from one another about 

 half an inch. The brachial artery divides here into two trunks, 

 radial and ulnar ; and the recurrent radial and ulnar branches 

 appear in the space, the former on the outer, and the latter on 

 the inner side. 



Two or three lymphatic giands lie on the sides of the artery, 

 and one below its point of splitting. 



MUSCLES ON THE FRONT OF THE FOREARM (fig. 24). The 

 muscles on the front of the forearm are divided into a superficial 

 and a deep group. 



In the superficial group there are five muscles, which are fixed 

 to the inner condyle of the humerus by a common tendon, and lie 

 in the undermentioned order from the outer to the inner side : 

 (1) pronator radii teres, (2) flexor carpi radialis, (3) palmaris longus, 

 (4) flexor carpi ulnaris ; and deeper and larger than any of these 

 is (5) the flexor sublimis digitorum. 



The deep group will be met with in a subsequent dissection 

 (p. 67). 



The PRONATOR RADII TERES (fig. 24, s ) arises from the inner condyle 

 of the humerus by the common tendon, from the ridge above the 

 condyle by fleshy fibres (fig 17, p. 44), from the fascia over it, from 

 the septum between it and the flexor carpi radialis, and by a second 

 tendinous slip from the inner edge of the coronoid process of the 

 ulna. It is inserted by a flat tendon into an impression, an inch in 

 length, on the middle of the outer surface of the radius (fig. 36, p. 86). 



The muscle is superficial except at the insertion, where it is 

 covered by the radial artery, and some of the outer set of muscles, 

 viz., supinator longus. and radial extensors of the wrist. The 

 pronator forms the inner boundary of the triangular space in front 

 of the elbow ; and its inner border touches the flexor carpi radialis. 

 By gently separating the muscle from the rest, it will be found to 

 lie on the brachialis anticus, the flexor sublimis digitorum, and 

 the ulnar artery and the median nerve, the small deep head of 

 origin intervening between the artery and nerve. 



