274 A MANUAL OF ANATOMY. 



Insertion. Into the middle third of the lower surface of 

 the clavicle, between the conoid and rhomboid ligaments. 



Nerve Supply. Supraclavicular, from the first trunk of 

 the brachial plexus (fifth and sixth nerves). 



Action. To depress and draw forward the clavicle, to 

 prevent outward displacement of the clavicle. 



Pectoralis Minor. Fig. 62. 



Origin. By three slips from the anterior surfaces and 

 upper borders of the third, fourth, and fifth ribs near their 

 cartilages. From the intercostal aponeurosis of the in- 

 cluded spaces. 



Insertion. Into the inner side and tip of the coracoid 

 process of the scapula, and inner side of the tendon of the 

 coracobrachialis and biceps muscle. 



Nerve Supply. The internal anterior thoracic from the 

 inner cord (eighth and first dorsal nerves). 



Action. (i) On the scapula. To depress, adduct, and 

 draw forward the shoulder. (2) On chest. If the scapula 

 is fixed it will tend to spread the ribs and raise them, thus 

 assisting in inspiration. 



DISSECTION. 



Section the pectoralis minor near its insertion, turn the inner part inward 

 and save the nerve and blood supply to it. 



Complete the dissection of the axillary space, beginning with the axillary 

 vein, which can be removed between two ligatures (one at its beginning and 

 one at its ending), after studying it carefully and noting its relations. 



Observe the location of the lymphatic glands, especially those along the 

 long thoracic artery and axillary vein. 



Trace the branches of the axillary artery, the nerves contained in the 

 axilla, and clean the presenting surfaces of the subscapularis, serratus mag- 

 nus, teres major, and latissimus dorsi muscles, being sure to remove all the 

 tissue rilling the space between the various muscles. 



The Lymphatics. 



The axillary lymphatics are from ten to twelve in num- 



