Axillary Fascia 239 



having traversed the costo-coracoid membrane (p. 240), runs over the 

 first part of the axillary artery to end in the highest part of the axillary 

 vein. 



The cutaneous nerves. In the pectoral region are supra-clavi- 

 cular branches of the third and fourth cervical nerves, the endings of 

 the intercostal nerves, and of their lateral branches. In the scapular 

 region of the chest the cutaneous nerves come from the posterior 

 divisions of the dorsal nerves, and from the lateral cutaneous branches 

 of the intercostals. In the deltoid region are the acromial twigs of 

 the supra-clavicular nerves, as shown on p. 145, and branches of the 

 circumflex. 



Down the arm the superficial nerves come (on the inner side) from 

 the intercosto-humeral, the internal and the lesser internal cutaneous, 

 and the musculo-spiral ; and, on the outer aspect, from the circumflex 

 and musculo-spiral. (See Brachial Plexus, p. 249.) 



The intercosto-humeral nerve, the lateral cutaneous branch of 

 the second intercostal, runs across the axilla to join the lesser internal 

 cutaneous in the supply of the skin as far as the inner condyle. Im- 

 plication of this nerve in cancerous invasion and in abscess of the 

 axilla causes neuralgic pain along the inner side of the arm. The 

 nerve is generally seen when the axilla is opened for the removal of 

 cancerous lymphatics in scirrhus mammas. 



The axillary fascia is the deep and important layer which is 

 continued from the front of the pectoralis major, across the floor of the 

 space, and backwards over the latissimus dorsi. It is attached above 

 to the clavicle, and in front to the sternum and chest. At the lower 

 border of the pectoralis major it becomes continuous with the fascial 

 investment of the pectoralis minor, and so, indirectly, with the costo- 

 coracoid membrane and also with the sheath of the axillary vessels. 

 Below the armpit it is continuous with the fascia around the arm. It 

 is strong and well able to shut in an axillary abscess. 



The deep fascia of the arm surrounds the limb, and is continuous 

 above with that covering the deltoid and pectoralis major. It is 

 strengthened by slips from the insertions of the deltoid, pectoralis 

 major, and latissimus dorsi, and gives off strong intermuscular septa to 

 the condylar ridges and condyles. The inner of these septa is pierced 

 by the inferior profunda and the anastomotica magna, the former vessel 

 being accompanied by the ulnar nerve. The musculo-spiral nerve 

 and superior profunda artery pass through the outer septum. 



Below, the deep fascia of the arm is continuous with that of 

 the forearm, and is attached to the olecranon process, but it is not 

 attached to the head of the radius, or it would check its rotatory move- 

 ments. 



The pectoralis major arises from the inner half of the clavicle, 

 the front of the sternum and the adjacent costal cartilages, and from 

 the aponeurosis of the external oblique. It is inserted into the outer 



