216 ANATOMICAL TECHNOLOGY. 



trad of the point of crossing, the interval between the two muscles is 

 filled with a fascia so dense as to practically unite them. 



Lift the skin from 1-2 cm. along the occipito-presternal line. 

 Dissect up the caudal border of the clavo-trapezius for 2-3 cm. at 

 the junction of its dorsal and middle thirds, and pull it caudad. 

 This may serve to indicate the position of the ventro-cephalic bor- 

 der near the cut edge of the skin. Moreover, between the border 

 of the clavo-trapezius and the caudal border of the adjacent sterno- 

 mastoideus, just caudad of the ear, will be seen emerging one or 

 two nerves. 



Follow the border of the clavo-trapezius to the crista lambdoi- 

 dalis, noting that, for 15-20 mm. therefrom, it is closely united with 

 the caudal border of the adjacent sterno-mastoideus. The two 

 muscles may usually be separated without cutting fibers, but some- 

 times a slender fasciculus passes from one to the other obliquely at 

 about the middle of their length. 



Part of the occipital end of the muscle is covered by a small tri- 

 angular muscle belonging to the ear. This, the M. cervico-auricu- 

 laris (subcervico-pavilien of Straus- Durckheim, A, I, 194), is shown 

 in Fig. 66, but not named ; it must be removed with great care to a 

 point just cephalad of the crista lambdoidalis. Trace the ventro- 

 cephalic border of the clavo-trapezius to the clavicle, which may be 

 felt in the muscles between the prsesternum and the convexity of 

 the shoulder. 



Transect the muscle at its middle ; in reflecting the ventral end 

 of the muscle, use great care in separating it from the subjacent 

 clavo-mastoideus, which is also attached to the clavicle. After 

 reflecting the dorsal part, divide it lengthwise along a line corre- 

 sponding with the angle formed by the meson with the crista lambdoi- 

 dalis ; the wider of the strips so formed may then be reflected across 

 the meson, and the narrower upon the head, as shown in Fig. 67. 



616. Origin. In two parts : (A) by a thin tendon 5-10 mm. 

 long, from the mesal 10-15 inm. of the crista lambdoidalis ; (B) by 

 fleshy fibers from the supraspinous ligament for 4-5 cm. from the 

 crest to the caudal end of the axial neural spine (Fig. 30, 208, 471). 



Insertion. The details of the insertion differ considerably in 

 individuals, and perhaps in the same individual according to age 

 and the development of the clavicle. Sometimes the sternal end of 

 the clavicle projects about 1 mm. mesad of the M. clavo-trapezius ^ 



