NERVES OF THE UPPER EXTREMITY. 490 



and then divides into a palmar and a dorsal ramuscle: the 

 first being distributed to the muscles and integuments of the 

 thumb, the second terminating so as to supply the back of the 

 hand, of the thumb, fore, middle, and ring fingers to their ex- 

 tremities. 



8. The Nervus Medianus descends the arm at the inner 

 edge of the biceps muscle; along the anterior surface of the 

 brachial artery, adhering firmly to it, and the deep-seated veins, 

 by cellular substance. As far as the elbow, it sends off no 

 branch of importance. There it lies at the side of the biceps 

 tendon, crosses the lower part of the brachialis internus, and is 

 beneath the aponeurosis of the biceps. It then perforates the 

 pronator teres and gets between the flexor sublimis digito- 

 rum, and the flexor longus pollicis, and enters the palm of 

 the hand under the ligament of the wrist, at the radial edge of 

 the tendons of the flexor sublimis. In the palm it is situated 

 beneath the aponeurosis palmaris and the arcus sublimis of the 

 arteries. 



The median nerve dispenses the following branches: At 

 the bend of the arm, it furnishes filaments to the heads of the 

 first layer of muscles of the fore arm; and a little below, it de- 

 taches the nervus iriterosseus, which supplies filaments to the 

 flexor longus poliicis and flexor profundus digitorum. The in- " 

 terosseous nerve then descends with the interosseous artery in 

 front of the interosseous ligament, and terminates in the prona- 

 tor quadratus. 



Before the median nerve reaches the wrist, it sends a branch 

 which supplies with filaments the muscles and integuments of 

 the ball of the thumb. . In the palm of the hand, it divides and 

 subdivides so as to send a branch to each side of the thumb, of 

 the fore, and of the middle finger, and to one side of the ring 

 finger. These branches go along with the arteries to the ends 

 of the fingers and thumb. 



9. The Nervus Ulnaris comes from the lowest section of 

 the brachial plexus. It descends along the internal anterior 

 part of the triceps muscle, in a groove formed between it, and 

 the intermuscular ligament: it diverges, in this course, gradu- 

 ally from the median nerve till it reaches the elbow, when it is 



