568 



HUMAN ANATOMY. 



THE MUSCLES OF THE UPPER LIMB. 



THE MUSCLES EXTENDING BETWEEN THE AXIAL SKELETON 



AND THE PECTORAL GIRDLE. 



{a) THE PRE-AXIAL MUSCLES. 



I. Pectoralis major. 2. 



3. Subclavius. 



Pectoralis minor. 



The Pectoral Fascia. — The superficial pectoral fascia is continuous above 

 with the superficial cervical and below with the superficial abdominal fasciae, and 

 covers the entire anterior wall of the thorax. It usually contains a considerable 

 amount of fat and has embedded in it the mammary gland. 



The deep fascia is attached above to the clavicle, and forms a thin membrane 

 closely adherent to the surface of the pectoralis major, at the lower border of which 



Fig. 556. 





External anterior thoracic nerve 

 Cephalic vein 

 Branch of acromio-thoracic artery 



Deltoid 



Distal stump of_ 

 pectoralis major 



Cut edge of deei> 

 pectoral fascia 



Pectoralis minor enclosed \\\' 

 clavi-pectoral fascia 



Pectoralis major, cut edge 

 of clavicular portion 



v:.; . f:. 



Pectoralis major, cut 

 edge of sterno-costal 

 portion 



Dissection of thoracic wall after removal of greater part of pectoralis major, showing clavi-pectoral fascia 

 enclosing pectoralis minor and continuous with axillary fascia. 



it becomes continuous with the axillary fascia. Medially it is attached to the ventral 

 surface of the sternum and laterally it is continuous with the fascia covering the deltoid. 

 Beneath the deep fascia there arises from the clavicle a second sheet of fascia 

 {^clavi-pcdoral fascia) (Fig. 556) which encloses the subclavius muscle and is then 

 continued downward to the upper border of the pectoralis minor. There it divides 

 into two sheets which enclose the muscle and at its lower margin unite to form a 

 single sheet which becomes continuous with the axillary fascia close to the lower 

 b<^rder of the pectoralis major. The portion of this fascia which intervenes between 

 the clavicle and the subclavius muscle and the upper border of the pectoralis minor 

 is termed the coraco-clavicular fascia or costo-coracoid membrane. It is prolonged 

 laterally along the upper border of the pectoralis minor, over the upper portion of 

 the axillary vessels, to the coracoid process, its outer portion being thickened to form 



