432 MUSCLES. 



It is inserted, tendinous and fleshy, into the radial edge of 

 the metacarpal bone of the thumb, from its base to its head. 

 It draws the metacarpal bone inwards. 



3. The Flexor Brevis Pollicis Manus, 



Is beneath the abductor pollicis, and at the side of the oppo- 

 nens pollicis. A groove is formed in it by the tendon of the 

 flexor iongus pollicis, which divides it into two heads. 



The first head arises, fleshy, from the points of the trapezium, 

 trapezoides, and from the contiguous part of the internal sur- 

 face of the annular ligament, and is inserted into the outer sesa- 

 moid bone ; the sesamoid bone, like a patella, being connected 

 to the first phalanx of the thumb by a tendon. 



The second or internal head arises, fleshy, from the magnum 

 and unciforme, near their metacarpal surfaces, and from the 

 base of the metacarpal bone of the middle finger. It is inserted 

 into the inner sesamoid bone, which, like the external, is con- 

 nected, by ligament, to the first phalanx. 



The short flexor, as its name implies, bends the first phalanx 

 of the thumb. 



4. The Adductor Pollicis Manus, 



Lies in the palm of the hand, beneath the lumbricalcs and 

 the tendons of the flexor sublimis and profundus. It arises, 

 fleshy, from the ulnar edge of the metacarpal bone of the mid- 

 ble finger, between its base and head, and it is inserted, tendi- 

 nous, into the inner part of the base of the first phalanx of the 

 thumb, just above the sesamoid bone. 



It pulls the thumb towards the fingers. 



The Abductor Indicis Manus, 



Is on the radial edge of the hand, between the metacarpal 

 bones of the fore finger and thumb, and is just beneath the skin. 

 It arises tendinous from the trapezium, and fleshy from the ul- 

 nar edge of the metacarpal bone of the thumb, between its base 

 and head. 



