MUSCLES OF THE OS FEMORIS. 375 



Inserted into the outside of the tendinous expansion from tlie 

 extensor digitorum communis, which covers the posterior part of 

 the middle finger. 



Use. To extend and to draw the middle finger outwards. 



2. Posterior Medii, 



Arises, by two origins, from the roots of the metacarpal bones 

 next each other, that sustain the middle and ring fingers. 



Inserted into the inside of the tendinous expansion from the 

 extensor digitorum communis, which runs along the posterior part 

 of the middle finger. 



Use. To extend and draw the middle finger inwards. 



3. Posterior Annulaj-is, 



Arises, by two origins, from the roots of the metacarpal bones 

 that sustain the ring and little fingers, next each other. 



Inserted into the inside of the tendon on the back of the ring 

 finger. 



Use. To draw the ring finger inward. 



The following muscle also appears on the back of the hand. 



Adductor Indicis Manus, 



Arises, from the os trapezium, and from the superior part and 

 inner side of the metacarpal bone of the thumb. 



Inserted, by a short tendon, into the outer and back part of 

 the first bone of the fore finger. 



Use. To bring the fore finger towards the thumb. 



MUSCLES OF THE INFERIOR EXTREMITIES. 



These may be divided into the muscles situated on the out- 

 side of the pelvis, on the thigh, on the leg, and on the ybo^. 



The muscles on the outside of the pelvis, which are called 

 muscles of the thigh, 



Are composed of one layer before and three layers behind. 



The layer before consists of five muscles : 



1. Psoas Magnus. 



2. Iliacus Internus. 



i See page 346, 347. 



