222 ANATOMICAL TBGSNOLOOT. 



ear and parotid, for 2-3 cm., taking care not to cut caudad of the 

 crista. 



Then reflect the ventral flap for about the same distance. In the 

 depression just caudad of the mandibular angle note the firmer tex- 

 tured and darker colored submaxillary gland (Fig. 66, 87). Its 

 dorsal border is often quite firmly attached to the ventral border 

 and ectal surface of the sterno-mastoideus. Remove the gland, 

 together with the dense connective tissue in the groove between the 

 head and the neck ventrad of the origin of the occipito-scapularis. 



Along the ventral border of the space occupied by the submax- 

 illary gland is the Vena jugularis (Fig. 101), wliioh lies upon the 

 ectal aspect of the sterno-mastoideus, crossing very obliquely from 

 its ventral to its dorsal border. Divide the vein at the middle of its 

 length, reflect the ends and free the surface of the muscle from fat 

 and connective tissue. 



Dissection. — The dorsal border of the muscle is ajoparent at 

 about its middle, where it was crossed by the V. jugularis, and 

 where it in turn crosses the ventral border of the subjacent clavo- 

 mastoideus. Lift this border, taking care not to include the fibers 

 of the clavo-mastoideus. A little cephalad of the middle of the 

 length of the muscle dissect from the dorsal to the ventral border. 



In reflecting the cephalic part, note that the ventral border is 

 thickened as if folded upon itself, and that, at the occiput, the dor- 

 sal border may overlap the occlpito-scapidaris for half the width 

 of the latter. In reflecting the caudal part, note that, ahout the 

 middle of the length of the whole muscle, it joins its platetrope, the 

 fibers appearing to interdigitate to some extent (Fig. 72). About 

 2 cm. cephalad of the prfesternum the muscle is overlapped hy the 

 ectal lamina of the ectopectoralis. 



§ 624. Origin. — On account of the overlapping just mentioned, 

 the farther dissection of the sternal end of the muscle is better 

 deferred until after the examination of the ectopectoralis. 



Insertion. — The cephalic attachment of the muscle is by a tendon 

 2-7 mm. long which is inserted upon the crista lambdoidalis laterad 

 of, and usually overlapping to some extent, the origin of the occip- 

 ito-scapularis. The line of insertion extends not only along the 

 crista, hut also upon the rather sharp ridge of the mastoid process, 

 which ceases suddenly at a slight elevation just dorso-caudad of the 

 stylo-mastoid foramen, 3-4 mm. from the meatus. The tendon is 

 here a little thicker than at other points, and between it and the 



