PHYSIOLOGY : PRACTICUM I : PLATE IV. 



RIGHT AXILLARY REGION OF THE CAT AFTER DIVISION OF THE 

 PECTORAL MUSCLES. 



J t*. o a / a r Vein. 

 C/avi tfe, 



steruo-mastoid muscle 



The PECTORALS have been transected along the line X X as indicated in PI. III. 

 The distal portions have been reflected laterad upon the shoulder. The muscle marked H 

 in PI. Ill is everted so as to expose its ental surface and the CLAVICLE (collar-bone) 

 attached thereto ; the name points to the sternal end of the clavicle. The abbreviations 

 Dlt. and Tr. are upon the two portions of the muscle, corresponding to parts of the del- 

 toid and trapezius of man. 



The main object of the figure is to facilitate the recognition of the great vessels and 

 nerves which traverse the axillary space from the root of ihs neck to the arm. Farthest 

 caudad is the AXILLARY VEIN, joined by a branch, and itself uniting with the ECTO- 

 JUGULAR (external jugular) to form the BRACHIOCEPHALIC ; the unseen union of 

 this with its opposite forms the PRECAVA seen in PI. VII. Just cephalad of the vein is 

 the AXILLARY ARTERY. A few nerve trunks are shown ; their actual number is greater, 

 and their relations very complex, as may be seen from Anatomical Technology, Figs. 101, 

 102, 105, 106. The fat, connective tissue and smaller vessels and nerves are not shown. 



The capitals A G indicate portions of the pectoral mass similarly lettered in PI. III. 

 i, a cervical muscle. 2, the muscular attachment of the RECTUS MUSCLE. 3, its 

 thin tendon covering the second intercostals. 



