148 ANATOMICAL TECHNOLOGY. 



§ 224). Then press upon the side of the neck near the head and de- 

 termine the position of the wing of the atlas, diapopTiysis atlantalis 

 (Fig. 52, § 229) . Part the hair along a cando-cephalic line from about 

 midway between the wing of the atlas and the larynx, and then 

 commencing opposite the cephalic edge of the wing of the atlas, 

 carry an incision directly candad for 3-5 cm. Divaricate the skin, 

 and the external jugular vein will appear, full of blood. 



Injection. — Dissect the vein free as directed for the A. femoralis, 

 make a V-shaped incision, insert the canula, and then remove as 

 much blood as possible, as directed (§ 362). Finally, inject with 

 blue plaster (§ 343). 



It is imposgible to fill the small vessels with plaster on account of the valves (Fig. 103), 

 If one wishes to inject the venous system of the cat, it may be done successfully in most 

 cases by injecting blue gelatin into the jugular or femoral vein. See Appendix, § 1450. 



§ 367. Injection of the Arteria Carotidea. — Pos^wre.— The pos- 

 ture should be the same as for the V. jugularis externa (§ 366). 



Exposure.— M.^k.% an incision through the skin as directed for 

 the external jugular vein (§ 366). Dissect up the mesal edge of the 

 skin to the ventrimeson. Determine the position of the larynx, and 

 then make an incision 2-3 cm. long just laterad of the larynx and 

 through the sterno-mastoid muscle. Divaricate the cut edges of the 

 muscle, and there will be seen extending parallel with the trachea 

 the carotid artery, the vagus and sympathic nerves, and the V. 

 jugularis interna (Fig. 101). 



Dissection. — AVith the tracer and forceps, dissect the artery free 

 from the nerve and vein. Make a V-shaped incision, insert the 

 canula, and inject centrad as directed for the A. femoralis (§ 359). 



All the arteries of the body will be filled excepting those cephalad of the place of 

 injection on the side injected. To fill those, one must inject cephalad after the general 

 injection is made. 



References to Coarse Injections. — Bernard, A, 191, 363; Gage, i, 717 ; Harrison, 

 A, II, 865 ; Heath, A, 547 ; Hyrtl, A, 615 ; Straus-Durckheim, B, I, 90 ; Mojsisovics, A, 

 15-34. 



