DISSECTION OF THE UPPER EXTREMITY 



93 



palmaris longus runs in front of the ligamentum carpi trans- 

 versum (0. T. anterior annular ligament). The ulnar artery 

 and nerve also run superficial to the ligamentum carpi trans- 

 versum, though under cover of the more superficial ligamentum 

 carpi volare. (Cf. Spalteholz, Figs. 362 and 363.) Study care- 

 fully the form, position, origin, and innervation of each of the 

 following muscles : 



(a) Brachioradial muscle (M. brachioradialis) (0. T. supinator longus). 

 This will be studied more particularly later, when the back and 

 radial margin of the forearm are dissected. 



FIG. 32. 



Transverse section through the forearm of a human embryo of 4.5 cm. 



ai, anterior interosseous nerve ; C, M. centralis ; CR, M. condyloradialis ; CU, M. condylo-ulnaris ; 

 FCR, M. flexor carpi radialis; FCU, M. flexor carpi ulnaris; m, median nerve; PL, M. palmaris longus; 

 It, radius; Ra, M. radialis; U, ulna; u, ulnaf nerve; UL, M. ulnaris. The shaded areas represent the 

 M. flexor sublimis digitorum. (After McMurrich, Amer. Jour, of Anat., Baltimore, 1903, vol. ii., No. 2, 

 p. 200, Fig. 8.) 



(b) Long palmar muscle (M. palmaris longus). 



(c) Round pronator muscle (M. pronator teres) (0. T. pronator radii 



teres). 



(ca) Humeral head (caput humerale). 



(cb) Ulnar head (caput ulnare) (0. T. coronoid head). 



Note relation of ulnar head to median nerve and ulnar 

 artery. 



(d) Radial flexor muscle of wrist (M. flexor carpi radialis). 



