724 INTEROSSEOUS MUSCLES. 



the skin, covering the muscle of the little finger. Its fibres 

 are separated and are inserted into the cellular tissue and 

 integument. 



Function. To contract the skin of the palm and deepen 

 the hollow of the hand. 



The lumbricales (Fig. 232) are four in number, and situ- 

 ated below the anterior annular ligament. They each form 

 a small fleshy belly which arises from the radial side of 

 the tendons of the flexor profundus, and is inserted by a 

 flat tendon into the posterior part of the first phalanx of 

 each finger along with the tendinous expansion of the 

 extensor communis. 



Function. To bend the first phalanges. 



INTEROSSEOUS MUSCLES, (Figs. 232, 228.) 



Anterior interossei. These are three in number, and 

 occupy the palmar portion of the hand. They arise fleshy 

 and tendinous from the base and sides of the metacarpal 

 bone, and are inserted into the base and posterior part of 

 the first phalanx of the finger along with the tendinous 

 expansion of the common extensor. The first palmar inter- 

 osseous belongs to the fore-finger, the second to the ring- 

 finger, and the third to the little finger. 



Function. Adductors of the fingers. 



Posterior interossei. Are situated on the back of the 

 hand, and fill the interosseous spaces. They are four in 

 number, and arise fleshy, by two heads from the base and 

 sides of the metacarpal bones, and are inserted into the base 

 of the first phalanges along with the tendinous expansion 

 of the common extensor. 



Function. Abductors of the fingers. 



SECTION II. 

 FASCIA OF THE SUPERIOR EXTREMITY. 



The superior extremity is surrounded by an aponeurotic 

 membrane from the shoulder to the hand, investing all its 

 muscles externally, as well as sending processes between 

 them, and separating each from the other. 



