PHYSIOLOGY : PRACTICUM I : PLATE III. 



VENTRAL ASPECT OF THE THORACIC REGION OF THE CAT, reduced. The 

 animal is supposed to be on its back with the arms outstretched ; the direction of the arms 

 is such as might be assumed by the animal in climbing a thick tree ; the shoulders are 

 widened so as to resemble more nearly those of man ; the muscles are rendered tense so as 

 to be more readily distinguished and divided. 



JUGULAR 



The muscles of the neck, abdomen and brachium are vaguely indicated. Most of the 

 muscles here shown constitute the group called PECTORALS. The pectorals form two 

 layers, an ectal (superficial), the ECTOPECTORAL ; an ental(deep), the ENTOPECTOR- 

 AL ; with the former the general direction of the fibers is approximately transverse ; with 

 the latter, obliquely latero-cephalad. In man, the raccoon and a few others, the ectopec- 

 toral is much the larger, so that the names commonly applied (pectoralis major and p. mi- 

 nor ) are appropriate ; but in the cat, as in most mammals, the reverse is the case, and only 

 the more cephalic portion of the entopectoral is covered by the ectopectoral 



Each of the pectoral muscles in the cat consists of several laminae more or less easily 

 separable; besides those shown in the figure (A, B, C, D, E, G,) there is a seventh, a 

 part of the entopectoral, which is entirely hidden. 



H indicates a ribbon-like muscle which overlaps the pectorals at the shoulder and on 

 the brachium ; at about the middle of its length lies the CLAVICLE (collar-bone, Plates I 

 and II), small in the cat ; but in man it is large and the cervical and brachial parts are 

 separated by it. 



The interrupted line X X at the right of the MESON (middle line) indicates 



the incision to be made through the pectoral mass. 



' Defects. The fasciculus marked A lies too far cephalad. On the neck the word 

 MUSCES should be MUSCLES. 



