SHOULDER, ARM, FOREARM, AND HAND. 193 



The inner boundary is formed by six or eight ribs, their intercostal muscles 

 and fasciae, and six serrations of the serratus magnus muscle. (Fig. 132.) 



The angles are three in number, and the surgical importance of each is that 

 in these angles are found some structure or structures to be avoided, or reached 

 in surgical operations, (i) The anterior thoracic angle contains the long thoracic 

 artery ; (2) the posterior thoracic angle contains the subscapular artery and the 

 external phrenic nerve ; (3) the outer or Innncral angle contains the axillary 

 artery and nearly all the important branches of the brachial plexus. 



The Axillary Contents. On removing the anterior wall of the axilla, as 

 you may now complete doing, by cutting the pectoralis minor at its insertion, and 

 turning the same back, with its attached clavi-pectoral fascia, you will see (i) a 

 mass of axillary connective tissue containing some fat and blood-vessels, the alar 

 thoracic vessels, and axillary lymphatic glands. In health these glands are not 

 larger than a small pea, and are bluish in color. When diseased, as is frequently 

 the case in dissecting-room material, they are often very large ; they may be as 



CLAVICLE 



CORACOIO PROCESS 

 Supra-spinatus 



Subscapularis 



Teres major 

 Latissimus dorsi 



Coraco-brachialis and short 

 head of biceps 



Pectoralis major 



FIG. 136. FRONT VIEW OF THE SCAPULAR MUSCLES. THE POSTERIOR WALL OF THE AXILLA. 



large as a hazelnut, or even larger. Each student should visit every table in the 

 room, when this area is being dissected, to inspect the condition of these glands. 



To clean out the axilla means, in surgery, to remove the diseased axillary 

 glands. This operation is attended by slight hemorrhage. The vessels that 

 should bleed are the alar thoracics. These supply the glands and fat in this 

 space. The term unavoidable hemorrhage would be an excellent expression by 

 which to designate the bleeding incident to the removal of these glands, if this 

 expression were not already the stereotyped property of obstetric nomenclature. 



Systematic Examination of the Walls and Contents of the Axillary Space. 

 i. Examine the inner icall and find: (i) The outer surface of the six upper 

 ribs. (2) The serrations of the serratus magnus muscle. (Fig. 135.) (3) Coming 

 through two or three intercostal spaces, the second, third, fourth, some cuta- 

 neous nerves will be seen. These nerves cross the space and seem to become lost 

 in the mass of fat you have just examined. These nerves are the posterior lateral 

 'cutaneous branches of the intercostal nerves. Now trace them out as follows : 

 One passes out under the pectoralis major muscle to the skin of this muscle, in 

 front ; a second passes out behind, around the latissimus clorsi, to the skin of 

 this muscle ; a third passes down the center of the space, joins a branch of the 



