216 



MUSCLES OF THE UPPER LIMB. 



wards, and ends in a flat tendon which turns over the radius, and is inserted 

 into a rough surface at the middle of the outer side of that bone. 



Fig. 179. 



Fig. 179. SUPERFICIAL MUSCLES OF THE FOREARM 

 AND HAND, SEEN PROM THE FRONT. 



3, biceps flexor cubiti ; 3', its tendon of insertion ; 

 3", its aponeurotic slip ; 4, brachialis anticus ; 4', 

 its inner and lower portion ; 5', lower part of the 

 triceps, seen rising from behind the intermuscular 

 septum ; 6, pronator radii teres ; 7, flexor carpi 

 radialis ; 8, palmaris longus, passing at 8' into the 

 palmar aponeurosis ; 9, flexor carpi ulnaris ; 10, 

 supinator longus ; between 10 and 3, f marks a 

 part of the supinator brevis ; 11, extensor ossis 

 nietacarpi pollicis ; 12, extensor primi internodii ; 

 13, lower part of the flexor digitorum sublimis ; 14, 

 flexor longus pollicis ; 15, small part of the flexor digi- 

 torum profundus ; 16, palmaris brevis, lying on the 

 muscles of the little finger ; 17, abductor pollicis. 



The pronator teres is placed superficially in the 

 greater part of its extent; but towards its inser- 

 tion it is crossed by the radial artery and nerve, 

 and the supinator longus muscle. The ulnar bor- 

 der is in contact with the flexor carpi radialis 

 and palmaris longus : the radial border forms the 

 inner boundary of the angular space at the bend of 

 the arm, in which are placed the brachial artery, 

 the median nerve, and the tendon of the biceps 

 muscle. The pronator teres covers the flexor sub- 

 limis digitorum ; the ulnar artery passes behind 

 the whole muscle, and the median nerve between 

 its two heads. 



Additional fibres frequently arise from the inter- 

 muscular septum above the inner condyloid emi- 

 nence of the humerus, or from the supracondy- 

 loid process when that'is present. This peculiarity 

 is sometimes associated with a change in the 

 direction of the brachial artery. 



The flexor carpi radialis arises from the 

 inner condyle by the common tendon, from 

 the fascia of the forearm, and from the inter- 

 muscular septa placed between it and the 

 pronator teres on one side, the palmaris longus 

 on the other, and the flexor sublimis pos- 

 teriorly. The fleshy fibres end in a flat 

 tendon, a little below the middle of the 

 forearm. Arrived at the carpus, the tendon 



occupies a special fibrous compartment situated in the outer part of the 

 anterior annular ligament of the wrist, and runs through a groove in the 

 os trapezium, to which it is bound by a thin fibrous sheath lined by a 

 synovial membrane, and is inserted into the extremity of the second 

 metacarpal bone. 



A fasciculus from the inserted tendon sometimes passes to the third and even to 

 the fourth metacarpal bone. 



In the lower half of the forearm the radial artery is placed to the outer side of the 

 tendon. 



