298 ANATOMY OF THE RABBIT 



petromastoid bones near the tip of the squamosal process of the parietal. As it 

 runs along the lower margin of the temporal muscle, it is joined by one or more 

 small deep temporal veins from the substance thereof. The posterior facial is 

 joined by the anterior auricular vein from the ear and then passes downward 

 through the parotid gland, receiving the small transverse facial vein and being 

 crossed by the facial nerve. Immediately below the latter it receives the posterior 

 auricular vein from the ear and the back of the head. At about the same 

 level it is joined by a deep vessel, the posterior internal maxillary, emerging 

 from behind the mandible. 



In addition to the tributaries described above (p. 294), the 

 anterior facial vein receives 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. It is also identified as the 

 sublingual vein. 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. 



An anastomotic branch connects the deep facial vein with the inferior 

 alveolar vein through the foramen at the ventral end of the sulcus ascendens of 

 the mandible. This provides an outlet through the latter vein for the blood from 

 the former when its passage is obstructed by the pressure of the contracting 

 masseter and internal pterygoid muscles. 



A small, unpaired median submental vein enters the anterior facial of 

 one side. 



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), one of the 

 salivary series, is a somewhat compact rounded or oval 

 gland lying at the medial side of the extreme ventral portion 

 of the angle of the mandible. Its whitish-coloured duct 

 (d. submaxillaris) may be seen running upward and slightly 

 forward to enter the mouth (cf. p. 307). It crosses the 

 lateral surface of the digastric muscle but is medial to the 

 external maxillary artery and is approximately paralleled 



