NERVES 163 



scapula, long head of the triceps and humerus, and, having 

 given an articular branch to the shoulder-joint, divides into 



Anterior branch : winds round neck of the humerus, supply- 

 ing deltoid and skin. 



Posterior branch : gives a branch to teres minot, which has 

 a gangliform swelling upon it ; also branches to deltoid and 

 integument. 



Cutaneous appears at posterior border of deltoid, supplies 

 skin over lower of muscle. 



Internal cutaneous (inner cord) : lies in front of 3rd part 

 of axillary artery, becomes cutaneous about middle of arm, 

 and divides into two branches 



Anterior : passes behind median basilic vein, supplies front 

 of inner side of forearm as low as wrist. 



Posterior : winds over internal condyle, supplying the back 

 of inner side of forearm to about the middle. 



Lesser internal cutaneous (nerve of Wrisberg) (inner cord) : 

 lies to inner side of axillary vein, communicates with the 

 intercosto-humeral, and then descends along inner side of 

 brachial vessels to middle of the arm, where it becomes 

 cutaneous and supplies integument of inner side as far as 

 inner condyle. It communicates with the posterior branch 

 of the larger internal cutaneous. 



Musculp-cutaneous (outer cord) : perforates coraco-brachi- 

 alis, passing to outer side of arm between biceps and 

 brachialis anticus, supplying the three named muscles ; fila- 

 ments also are given to the elbow-joint ; becomes cutaneous 

 just above elbow, and, passing behind median cephalic vein, 

 divides into 



Anterior cutaneous branch: passes along radial border of 

 forearm, supplying ball of thumb and joining the radial. 



Posterior cutaneous branch : supplies integument of lower 

 3rd of back of forearm on the radial side ; joins branches of 

 radial and musculo-spiral (external cutaneous branch). 



Median : arises by two roots, one from the outer cord, the 

 other from the inner cord of the plexus, which cresses 3rd 

 part of axillary artery to join the outer head. At first the 

 nerve lies to the outer side of the axillary artery, but about 

 the middle of the arm it crosses the brachial artery to reach 

 the 'inner side ; it then passes between the two heads of 

 the pronator radii teres, and is continued straight down 

 the forearm upon the flexor profundus, and beneath the 

 flexor sublimis ; at the wrist it lies between the tendons 

 of the flexor sublimis and flexor carpi radialis. Passing 

 beneath the annular ligament, it becomes somewhat 



