212 ANATOMICAL TECHNOLOGY. 



610. Caution. In making all incisions through the skin of 

 the cat, it is necessary, in addition to the general directions in 599, 

 to keep in mind the presence of the M. dermo-humeralis ( 629) and 

 other muscles constituting the panniculus carnosus, a thin muscu- 

 lar layer between the skin and the proper skeletal muscles. 



The dermal muscle is usually to be divided and lifted with the 

 skin. With fleshy animals, the risk of cutting at the same time 

 the underlying skeletal muscles is obviated by the intervention of a 

 layer of fat which should also be removed with the skin ( 600). 

 With lean animals, the two sets of muscles may usually be distin- 

 guished from the thinness and paleness of the dermal layer, and 

 from the fact that it is moved when the skin is pulled in any 

 direction. 



Connect ( 584) the prcesternum (Fig. 30 and 49, 228), with the 

 thirteenth tJioracic neural spine (Fig. 30 and 66, 227), and with a 

 point 1 cm. cephalad of the crista lambdoidalis (Fig. 56, 226). 



The occipito-presternal incision should have a slight caudal con- 

 vexity so as to skirt the base of the ear. The vertebro-presternal 

 incision should cross the brachium at about the junction of its first 

 and second fourths ; this incision may be commenced at the middle 

 of its length, and be carried thence in both directions. Lift the flap 

 at the presternal angle, and remove with the skin the fat, connective 

 tissue and dermal muscles. Reflect it across the dorsimeson. 



M. SPINO-TRAPEZIUS. 



611. Synonymy. The caudal part of the human trapezius, Q,, A, 1, 187 ; G., A, 

 373; dorso-cucullaire, S. D., A, TI, 334; portion dorsale du trapeze, Ch., A, Fig. 90, 

 " 1," 216 ; dorsal trapezim, Ch. (Fl.), A, 203 ; hinder portion of the trapezius, Miv., B, 137. 



Figures. Ectal aspect (66) ; insertion (67, 44); transection (99, 100). 



General Description. An elongated triangle, from the thoracic 

 dorsimeson to the mesoscapula and the surface of the MM. supra- 

 spinatus and infraspinatus. 



Dissection. The ventro-caudal border will appear as a slightly 

 raised line nearly parallel with the presterno- vertebral margin of 

 the skin. In recent specimens the color of the muscle is usually a 

 brighter red than that of the subjacent M. latissimus. 



Lift the border near its middle, and trace it mesad, noting that, 

 about 1 cm. from the meson, the muscular fibers are replaced by a 

 thin tendon which is not always easily separated from the subjacent 

 muscle. Then trace the border ventro-cephalad, noting that it 



