THENAR AND HYPOTHENAR MUSCLES IOQ 



Action. It assists in both flexion and supination of the forearm. 

 (This muscle was formerly called the long supinator.) 



Nerve. Radial. 



Annular Ligaments 



These are special bands of deep fascia holding in place those 

 tendons which pass the wrist-joint. They include the tendons in 

 canals through which they glide freely. Friction is prevented by 

 synovial sheaths within the canals. The fascia which binds down 

 the extensor tendons is the dorsal ligament of the wrist; that which 

 confines the flexor tendons is the transverse ligament of the wrist. 



MUSCLES OF THE PALM (Fio. 87) 



There is a group of palmar muscles which move the thumb in 

 various directions (flexion, abduction, adduction, and so on). 

 They form the elevation called the thenar eminence, or the "ball 

 of the thumb." A similar group for the little finger forms the 

 hypothenar eminence. 



They arise mostly on carpal bones and deep fascia and are inserted on first 

 phalanges. In the hollow of the hand between these two eminences lie the 

 long tendons, already described, on their way to the fingers; also some small 

 muscles between them and beneath them. 



The interosseous muscles fill the interosseous spaces. The action of the 

 dorsal group is to spread the fingers apart (abduction) while that of the palmar 

 group is to bring them together (adduction). 



Note. A line drawn from the middle of the wrist to the tip of the middle 

 finger is called the median line of the hand. To abduct the fingers and thumb 

 is to draw them away from this line in other words, from the middle finger. 

 To adduct them is to draw them toward the middle finger. 



Nerves. To the hypothenar muscles. Ulnar. To thenar muscles. 

 Median and ulnar. To inter ossei. Ulnar. 



The muscles in the palm are covered by particularly dense, 

 deep fascia called the palmar fascia, or palmar aponeurosis. 



MUSCLES OF THE LOWER EXTREMITY 



The Pelvis Interior 



False pelvis. The iliacus is the only muscle in the false pelvis; 

 it is already described with the psoas major, page 99. 



