178 SURGICAL APPLIED ANATOMY. [Chap. x. 



trunks serve to explain the diffusion of the pain 

 that is sometimes observed in painful affections of 

 the gland. Thus in abscess of the breast pain is 

 often felt round the side of the thorax to the back, 

 following the trunks of the above-named intercostal 

 nerves ; or it is distributed over the scapula by the 

 cutaneous branches of the posterior divisions of such 

 dorsal nerves as correspond to the intercostal trunks 

 that supply the breast ; or it runs down the arm 

 along the intercosto-humeral nerve (a branch of the 

 second intercostal), or shoots up the neck, probably, 

 along the supra clavicular branch from the cervical 

 plexus, which communicates with the same intercostal 

 trunk. 



The gland is supplied by the following arteries, 

 which are divided in excision of the organ : the 

 second, third, fourth, and fifth intercostal branches 

 of the internal mammary artery, some few branches 

 from the corresponding intercostal vessels, the long 

 thoracic artery, and the external mammary. The 

 majority of the lymphatics from the breast proceed to 

 the axilla. Some few follow the mammary branches 

 of the internal mammary artery, and enter the 

 anterior mediastinal glands, which are consequently 

 often found enlarged in cancer of the organ. 



As the chief blood supply of the breast conies 

 from the axilla, and as the main lymph vessels pro- 

 ceed to that region, it follows that malignant growths 

 of the gland tend to spread towards the axilla rather 

 than towards the middle line. 



2. The thoracic viscera. 



The limy. The apex of the lung rises in the neck 

 from one to two inches above the anterior end of the 

 first rib. The anterior edges of the two lungs lie be- 

 hind the sterno-clavicular articulations, pass obliquely 

 behind the manubrium, and meet in the middle line at 

 the junction of the manubrium with the gladiolus. The 



