MUSCLES OF THE HAND. 431 



Beneath the Aponeurosis Palmaris are placed the long flexor 

 tendons, and many of the small muscles of the hand. 



The Lumbricales, 



Are conspicuous ; they are four in number, of the size and 

 shape of earth worms. They arise, tendinous and fleshy, from 

 the radial sides of the tendons of the flexor profundus, beneath 

 the ligamentum carpi annulare anterius, and a little beyond its 

 inferior edge. 



They terminate in little flat tendons, which run along the outer 

 or radial edge of the fingers, and are inserted respectively into 

 the tendinous expansion of the extensor communis on the back 

 of the first phalanx of each finger, about its middle. 



They bend the first phalanges.* 



Four muscles constitute the ball of the thumb. 



1. The Abductor Pollicis Manus, 



Arises, tendinous and fleshy, from the anterior surface of the 

 ligamentum carpi annulare, and from the projecting ends of the 

 trapezium and scaphoides. 



It is inserted, tendinous, into the outer side of the base of the 

 first phalanx of the thumb, and into the tendinous membrane 

 derived from the extensors on its back part. 



It draws the thumb from the fore fingers. This muscle is 

 next to the skin. 



2. The Opponens Pollicis , 



Is beneath the abductor, and without its removal can scarcely 

 be seen. It arises, tendinous and fleshy, from the projecting 

 point of the os trapezium, and from the adjacent part of the an- 

 nular ligament. 



* Varieties. Sometimes one is deficient? sometimes one or more is double, in 

 which case the supernumerary goes to the ulnar edge of the adjoining finger. 



