The; Head and Neck. 159 



the transverse scapular vein (v. transversa scapulae) of the shoulder and 

 its union with the vein of the other side by the transverse jugular vein 

 (v. jugularis transversa) (Fig. 52). 



The posterior facial vein (v. facialis posterior) is formed below the 

 base of the ear by the union of the superficial and deep temporal veins 

 of the temporal region, the inferior ophthalmic vein, from the posterior 

 portion of the orbit, and the anterior auricular vein from the ear. It 

 passes downward in the substance of the parotid gland, and in its first 

 portion is covered by the root of the facial nerve. Immediately below 

 the latter it receives the posterior auricular vein from the ear and back 

 of the head. 



In addition to the tributaries described above, the anterior facial 

 vein deceives from beneath the anterior margin of the masseter the deep 

 facial vein (v. facialis profunda) . The latter arises in the lower anterior 

 portion of the orbit, and passes downward beneath the masseter muscle. 

 The anterior facial vein receives at the ventral border of the mandible 

 the internal maxillary vein (v. maxillaris interna). The latter also 

 begins in the orbit, where it is connected with the deep facial. At the 

 medial surface of the mandible it receives the inferior alveolar vein — to 

 be seen at a later stage — from the interior of the mandible. 



The external jugular vein may be divided and turned forward together with the 

 parotid gland. 



4. Examination of the more superficial structures of the ventral 

 surface of the head and neck. 



(a) The submaxillary gland (gl. submaxillaris), a somewhat 

 compact rounded or oval gland lies at the medial side of the 

 extreme ventral portion of the angle of the mandible. Its 

 duct (d. submaxillaris) may be seen running forward toward 

 the mouth. 



(b) The angle of the mandible is covered by two muscles of 

 mastication, the masseter lying on the lateral surface, and 

 the pterygoideus internus on the medial surface. 



(c) The digastricus. Only its insertion portion is visible. It 

 passes forward along the medial surface of the mandible, to 

 the anterior portion of which it is attached. 



(d) The mylohyoideus is a transverse sheet of muscle arising 

 from the medial surface of the mandible on either side and 

 inserted on the hyoid bone. 



(e) The sternomastoideus. Origin: In common with that of 

 the opposite side, from the manubrium sterni. Insertion: 

 Mastoid process of the skull. 



(f) The sternohyoideus. Origin: In common with that of the 

 opposite side, from the dorsal surface of the manubrium and 

 anterior portion of the body of the sternum, extending to the 

 third costal articulation. Insertion: Greater cornu of the 

 hyoid. 



The two muscles are closely associated in the middle line. They 

 should be separated from one another and divided. 



