DISSECTING MANUAL. 



It is attached internally to the first costal cartilage and exter- 

 nally to the coracoid process, a thickened portion (costo-cora- 

 coid ligament} connecting these points. Below the Pectoralis 

 minor it passes under the Pectoralis major and outward to 

 join the axillary fascia. [321] 



Back. The superficial fascia is not peculiar. The deep 

 fascia is attached mesially to the supraspinous ligament and 

 vertebral spines, and laterally to the spine of the scapula 

 and the clavicle; below the arm it is continuous, around the 

 Latissimus dorsi, with the axillary and abdominal fascise. As 

 the vertebral aponeurosis, concealing the Erector spina?, it is 

 attached to the angles of the ribs. [318] 



MUSCLES. 

 Pectoral Region. 



Pectoralis Major. Origin; (clavicular portion) inner half, 

 or two- thirds, of front of clavicle; (costo-sternal portion) an- 

 terior surface of sternum, by tendinous fibre decussating with 

 those of its fellow; first six costal cartilages; (abdominal por- 

 tion) a separate slip from the Obliquus externus aponeurosis. 

 Course; the muscle so twists on itself that the lower (costo- 

 sternal) fibres get behind the upper (clavicular) fibres and are 

 inserted higher on the humerus. Insertion; outer border of 

 bicipital groove of humerus, extending up to the great tuber- 

 osity and blending externally with the Deltoid insertion, and 

 internally with the Latissimus dorsi insertion. From the upper 

 border of the insertion a band ascends to the shoulder-joint 

 capsule, enveloping the Biceps tendon ; from the lower border 

 a fascial band descends to the fascia of the arm. [322] 



Pectoralis Minor. Origin; third, fourth, and fifth ribs near 

 their anterior ends; fascia over the third and fourth intercostal 

 spaces. Insertion; front of tip of coracoid process; (usually) 

 conjoint origin of Biceps and Coraco-brachialis. [324] 



Subclavius. Origin; upper surface of first costal cartilage, 



[114] 



