268 A MANUAL OF ANA TOMY. 



thence to the axillary glands. They follow along the long 

 thoracic artery. 



DISSECTION. 



Remove the superficial fascia from the same area as the skin, leaving the 

 deep fascia uninjured behind. 



The Deep Fascia. 



This is a very thin layer covering the pectoralis major. 

 Anteriorly it is attached to the front of the sternum, above 

 to the clavicle, externally it passes on to the deltoid muscle, 

 and below turns over the lower border of the pector- 

 alis major and stretches across the axillary space (axillary 

 fascia] to the latissimus dorsi muscle, which it covers. 

 Externally the axillary fascia passes into the deep fascia 

 covering the arm. 



The axillary fascia (and integument) is deeply hollowed 

 when the arm is extended to an angle of 45 degrees with 

 the trunk. This is due to the attachment of the fascia cov- 

 ering the pectoralis minor muscle. See page 270. 



DISSECTION. 



Remove the deep fascia, cutting parallel with the fibres of the muscle it 

 covers. In turning down the axillary fascia be careful to save the nerves 

 which will be found coming out from the axillary space. 



Clean the cephalic vein from the middle of the arm to where it disappears 

 through the costocoracoid membrane (see below), the branches of the 

 acromiothoracic artery, and the external anterior thoracic nerve. 



Pectoralis Major. Fig. 60. 



Origin. The clavicular portion, from the anterior sur- 

 face of the inner half of the clavicle. The sternal portion, 

 from the anterior surface of the sternum, from the anterior 

 surface of the second to sixth costal cartilages inclusive, 

 also, sometimes, the first and seventh cartilages, and from 

 the aponeurosis of the obliquus externus abdominis. 



Insertion. Into the anterior or external lip of the bicipi- 



