510 



NEUROLOGY. 



passing between the scapulo-ulnaris and caput parvum muscles, 

 it gains the inner side of the elbow. Afterwards, descending to 

 the bend of the carpus, it passes under the annular ligament and 

 divides into two branches, one of which unites with a branch 

 from the median, to constitute the external metacarpal nerve, and 

 the other, traversing the space between the tendons of the flexor 

 metacarpi externus and medius, is distributed by numerous 

 branches to the skin covering the radius, 

 carpus, and the outer side of the metacarpus. 

 This nerve accompanies the artery and vein of 

 the same name. 



In its course, the ulna nerve gives off a 

 branch which proceeds downwards between the 

 scapulo-ulnaris and pectoralis transversus, fur- 

 nishing many filaments to the latter ; be- 

 coming cutaneous, it is distributed to the skin 

 below the elbow. It also furnishes a branch 

 to the flexor metacarpi muscles. 



The MEDIAN NERVE, composed of fibres 

 from the two dorsal and the eighth cervical 

 nerves, descends the humerus in company with 

 the humeral artery to the inner side of the 

 elbow, runs down the side of the radius till it 

 reaches the carpus, and then, passing under 

 the posterior annular ligament, divides into 

 the internal metacarpal, and a branch to the 

 external metacarpal nerve. In its course it 

 gives off, under the brachial artery, a branch 

 to the pectoral muscles ; and near the middle 

 of the humerus, a long branch, the musculo- 

 cutaneous or antibrachial nerve, which passes 

 obliquely under the coraco-humeralis anf 

 coraco-radialis muscles ; here it divides, one 

 branch going to the humeralis externus, while 

 the other, passing between this muscle and 

 the coraco-humeralis, gains the inner aspect of 

 the arm, where it becomes subcutaneous, and ramifies on the 

 antibrachial fascia, sending its branches down to the carpus. The 

 median nerve also supplies numerous filaments to the elbow joint, 

 to the flexor muscles of the phalanges, and the internal flexor of 

 the metacarpus. 



FIG. 191. 



Carpal and metacaqjal 

 nerves internal aspect. 

 </, External branch of medi- 

 an ; r, Internal branch of 

 median, or internal meta- 

 carpal ; s, Internal branch 

 of cubital , s', External 

 branch of cubital ; t,Exter- 

 nal branch of median, and 

 internal branch of cubital 

 uniting to form external 

 metacarpal ; u, Communi- 

 cating branch uniting 

 metacarpal nerves ; v, In- 

 ternal digital. 



