AXILLARY SPACE 43 



The branches from the cords are 

 From the lateral cord : 



Nervus thoracalis anterior lateralis (O.T. External Anterior 



Thoracic) (from C. v., vi., vn.). 

 N. musculocutaneus (from C. v., vi., vn.). 

 N. medianus, caput lateralis (O.T. Outer Head of Median) (from 



C. v., vi., vn.). 

 From the medial cord : 



N. thoracalis anterior medialis (O.T. Internal Anterior Thoracic) 



(from C. viii., T. I.). 

 N. cutaneus antibrachii medialis (O.T. Internal Cutaneous) (from 



C. viii., T. i.). 

 N. cutaneus brachii medialis (O.T. Lesser Internal Cutaneous) 



(from T. I.). 

 N. medianus, caput medialis (O.T. Inner Head of Median) (from 



C. viii., T. i.). 



N. ulnaris (from C. viii., T. i.). 

 From the posterior cord : 



Nn. subscapulares (O.T. Upper and Lower) (from C. v., vi.). 



N. thoracodorsalis (O.T. Long Subscapular) (from C. vi., vn., 



VIII.). 



N. axillaris (O.T. Circumflex) (from C. v., vi.). 



N. radialis (O.T. Musculospiral) (from C. v., vi., vn., viii., T. i). 



In the above table the different spinal nerves from which the fibres 

 of the several branches are derived are indicated. 



Nn. Thoracales Anteriores. The anterior thoracic nerves 

 supply the pectoral muscles. They are two in number, the 

 lateral and the medial. The lateral anterior thoracic nerve 

 springs from the lateral cord of the plexus, passes forwards 

 across the lateral side of the first part of the axillary artery, 

 communicates, in front of the artery, with the medial nerve, 

 pierces the costo-coracoid membrane, and breaks up into 

 branches which end in the pectoralis major. The medial 

 anterior thoracic nerve is smaller than the lateral. It springs 

 from the medial cord of the plexus, passes forwards between 

 the axillary artery and vein, communicates, in front of the 

 artery, with the lateral nerve, gives twigs of supply to the 

 pectoralis minor, then pierces that muscle and ends in the 

 pectoralis major, which it supplies. The pectoralis major is, 

 therefore, supplied by both anterior thoracic nerves, the 

 pectoralis minor by the medial nerve alone. 



Nn. Subscapulares. The subscapular nerves are two in 

 number the upper and the lower. They spring from the 

 posterior cord of the plexus. After a very short course the 

 upper nerve sinks into and supplies the upper and posterior 

 part of the subscapularis. The lower subscapular nerve 



