ANATOMY OF A MONODACTYLOUS FOETUS 405 



lower extremity of the radius and into the carpus. At the 

 origin of the long tendon from the belly of the muscle there comes 

 off also a very short tendon which courses obliquely toward the 

 flexor surface of the radius and is inserted right alongside of and 

 practically blended with a part of the flexor digitorum profundus, 

 about three-quarters of the distance down the bone. 



This muscle is named the extensor carpi ulnaris because of its 

 superficial origin from the humerus and its insertion into the 

 carpus, and because it is the most medial of the extensor muscles 

 here found, and is in contact with the flexors. All the muscles 

 inserting into the carpus also show attachment to the lower end 

 of the radius, this attachment seeming to be due to a spreading 

 out of the tendon at its insertion, and so I do not think the 

 radial attachment here offers a serious obstacle to calling the 

 muscle the extensor carpi ulnaris. 



FLEXORS 



This group of muscles exhibits members of both the super- 

 ficial and deep layers and although badly disorganized it still 

 retains a somewhat closer homology to the normal divisions of 

 this group than is to be found in the extensors. 



SUPEEFICIAL GROUP 



First layer 

 1. Flexor carpi radialis (figs. 7 and 8, F.C.R.) 



Origin. By a broad fleshy head from the upper part of the 

 medial epicondyle of the humerus. 



Insertion. This muscle is fleshy in the upper half of the fore- 

 arm and has a long thin tendon coursing through the lower half 

 to be inserted into the lower end of the radius and into the carpus. 



The position of this muscle is along the lateral border of the 

 radius on its volar sui'face, although it appears to be dorsal due 

 to the rotation of the bone. 



From its attachments and position it can be quite safely 

 identified as the flexor carpi radialis muscle. 



THE /MEHICAX JOURNAL OK ANATOMY, VOL. 22, NO. 3 



