266 A MANUAL OF ANATOMY. 



will be seen extending about an inch below the border of 

 the clavicle. In this region, too, will be found the terminal 

 filaments of the sternal, clavicular, and (over the point of 

 the shoulder) the acromial nerves from the cervical plexus. 

 See page 91. 



Along the front of the chest are the terminal twigs of the 

 intercostal nerves, second to sixth inclusive, and perforating 

 branches of the internal mammary artery. At the side are 

 the lateral cutaneous branches of the intercostal nerves, 

 second to sixth inclusive. These perforate the fascia along 

 the mid-axillary line. One large one, the intercostohumeral, 

 must be saved. 



The Mammary Gland. 



The mammary gland is rudimentary in the male. In the 

 female it varies greatly in size. Usually it covers a space 

 represented by a circle whose centre is at the nipple (see 

 below), and whose diameter reaches from the third to the 

 sixth ribs inclusive. The nipple is usually over the fourth 

 intercostal space, four inches from the median line. It is 

 surrounded by a darker area the areola about one inch 

 in diameter. 



The arteries are the intercostal branches of the internal 

 mammary, through the second, third, and fourth spaces, 

 the long thoracic artery, and often an abnormal branch 

 (external mammary) from the axillary. 



The veins follow the arteries. 



The nerves are derived from the fourth, fifth, and sixth 

 intercostal nerves, and from the terminal filaments of the 

 clavicular branch of the cervical plexus. 



The Lymphatics are Important. 



The main lymphatic trunks proceed to the pectoral and 



