DISSECTION OF THE UPPER LIMB. 

 CHAPTER II. 



DISSECTION OF THE AXILLA. 



SECTION I. 



THE wall of the chest and the axilla, which are described in this Time for 

 Section, are to be dissected in six days, so that the senior student disseotlon - 

 may be free to begin work on the thorax. 



POSITION. The body is lying on the back, the thorax raised to a Position of 

 convenient height by a block, and the arm, being slightly rotated the body ' 

 outwards, is to be placed at a right angle with the trunk, a long 

 board being passed under the shoulders from side to side for the 

 support of the arms when they are drawn out from the body. 



SURFACE-MARKING. On the front of the chest is seen the pro- Siirfai-p- 

 minence of the mamma, large in the female, but small and rudi- 

 mentary in the male, with the nipple projecting from it near the Mammary 

 centre. In the male the nipple is placed most frequently over the 

 fourth intercostal space, sometimes over the fifth rib, and occasionally nippu>. 

 at a still higher or lower level. Its position in the female varies 

 greatly with the development of the mamma. 



Between the arm and the chest is the hollow of the axilla, in the Armpit, 

 outer part of which the large vessels and nerves of the limb are 

 lodged. The extent of this hollow may be seen to vary much with 

 the position of the limb to the trunk ; for in proportion as the arm 

 is elevated, the folds bounding it in front and behind are carried 

 upwards and rendered tense, and the depth of the space is dimi- 

 nished. In this part the skin is of a dark colour, and is furnished 

 with hairs and large sweat-glands. 



If the arm is forcibly raised and moved in different directions, Head of the 

 while the fingers of one hand are placed in the armpit, the head of umerus> 

 the humerus may be recognised. 



On the outer side of the limb is the prominence of the shoulder ; Shoulder 



.... . ' arch of bone. 



and immediately above it is an osseous arch, which is formed m 

 front by the clavicle, behind and externally by the spine and the 

 acromion process of the scapula. Continued downwards from intermus- 

 about the middle of the clavicle is a slight depression between the 

 pectoral and deltoid muscles, and by pressing the fingers into this 

 hollow the coracoid process of the scapula can be made out. A 

 second groove, extending outwards from the sternal end of the 



