THE ANTIBRACHIAL MUSCLES. 



593 



band. The entire muscle is some- 

 times incompletely separated from 

 the neighboring muscles of the su- 

 perficial layer, receiving accessory 

 heads from the palmaris longus or 

 the flexor sublimis digitorum. 



2. Flexor Carpi Radialis 



(Fig. 576). 



Attachments. — The flexor 

 carpi radialis arises from the inner 

 condyle of the humerus, by a 

 tendon common to it and the 

 neighboring muscles of the super- 

 ficial layer, from the adjoining 

 intermuscular septa and the deep 

 fascia. It passes downward and 

 slightly laterally and is inserted 

 into the bases of the second and 

 third metacarpal bones. 



Nerve-Supply. — By the 

 median nerxe from the sixth cer- 

 vical nerve. 



Action. — To flex the hand 

 and to assist in pronating the 

 forearm. 



Relations. — In its course 

 down the forearm the flexor carpi 

 radialis passes obliquely across 

 the flexor sublimis digitorum and 

 the lower part of the flexor longus 

 pollicis. At the wrist it passes 

 through a special sheath within 

 the superficial part of the anterior 

 annular ligament, and just before 

 its insertion it is crossed by the 

 tendon of the flexor longus pol- 

 licis. A bursa (bursa m. flexoris 

 carpi radialis) is interposed be- 

 tween the tendon and the base 

 of the second metacarpal bone. 

 Laterally the muscle is in contact 

 above with the pronator radii 

 teres and below with the brachio- 

 radialis, from which it is sepa- 

 rated near the wrist by the radial 

 artery. 



3. Palmaris Longus 



(Fig. 576). 



Attachments. — The pal- 

 maris longus arises with the 

 neighboring superficial muscles 

 by the common tendon from the 

 inner condyle of the humerus, 

 from the adjoining intermuscular 

 septa, and from the deep fascia. 

 It forms a short spindle-shaped 

 belly which is continued into a 



Fig. 576. 



Brachialis anticus 



Brachio-radialis 



Flexor carpi 

 radialis 



Extensor carpi 

 radialis longior 



Styloid process — , 



Extensor ossis 



metacarpi 



pollicis 



Biceps 



j Internal 



/ condyle 



Pronator 

 radii teres 



Palmaris 



1 longus 



Flexor 



sublimis 



digitorum 



L| — Flexor carpi ulnaris 



Flexor carpi ulnaris 

 tendon 



Palmaris brevis 



Palmar fascia 



U-^ 



Superficial dissection of forearm and palm, anterior surface; 

 portion of antibrachial fascia covering origin of superficial muscles 

 has been left in place. 



38 



