642 



THE BEACHIAL PLEXUS. 



the three nerves giving rise to one large upper cord. The eighth cervical 

 and first dorsal nerves are united in another lower cord whilst they are 



Fig. 425. 



Fig. 425. DEEP DISSECTION OF THE AXILLA, SHOWING THE BRACHIAL PLEXUS AND 

 NEIOHBOUKING NERVES (from Sappey after Hirschfeld and Leveille). 



The clavicle has been sawn through near its sternal end, and is turned aside with the 

 muscles attached to it ; the subclavius, and the greater and lesser pectoral muscles have 

 been removed from the front of the axilla. 1, loop of union between the descendens noni 

 and a branch of the cervical plexus ; 2, pneumo-gastric ; 3, phrenic passing down to the 

 inner side of the scalenus anticus muscle ; 4, anterior primary division of the fifth cervical 

 nerve ; 5, the same of the sixth ; 6, 7, the same of the seventh and eighth cervical nerves ; 

 8, the same of the first dorsal nerve ; 9, 9, branch from the plexus to the subclavius 

 muscle, communicating with the phrenic nerve; 10, posterior thoracic nerve distributed 

 to the serratus magnus ; 11, upper anterior thoracic nerve passing into the great pectoral 

 muscle ; 13, lower anterior thoracic distributed to the lesser pectoral ; 14, twig of com- 

 munication between these two nerves ; 12, suprascapular nerve passing through the supra- 

 scapular notch ; 15, lower of the two subscapular nerves ; 16, nerve of the teres major ; 

 17, long subscapular, or nerve of the latissimus dorsi ; 18, accessory of the internal 

 cutaneous nerve ; 19, union of the accessory cutaneous with the second and third inter- 

 costal nerves ; 20, lateral branch of the secoud intercostal ; 21, second internal cutaneous 

 or nerve of Wrisberg ; 22, internal cutaneous nerve ; 23, the ulnar nerve to the inside of 

 the axillary artery, passing behind the vein, and having, in this case, a union with the 

 upper division of the plexus ; 24, the median nerve immediately below the place where its 

 two roots embrace the artery, which is divided above this place; 25, the musculo-cutaneous 

 nerve passing into the coraco-brachialis muscle; 26, the musculo-spiral nerve passing 

 behind the divided brachial artery. 



