JUGULAR VEINS 685 



responding artery. Its radicles come from the posterior part of the temporalis 

 muscle and from the external ear. It receives the dorsal cerebral vein (V. cere- 

 bralis dorsalis), which is the emissary of the transverse sinus of the dura mater, and 

 emerges from the temporal canal behind the postglenoid process. The trans- 

 verse facial vein (V. transversa faciei) runs at first above the artery of like name, 

 then plunges deeply into the masseter and unites in front with the facial vein. It 

 is connected with the vena reflexa and with the posterior deep temporal vein by a 

 branch which emerges from the temporal fossa through the mandibular notch. 



3. The masseteric vein (V. masseterica) joins the jugular at the upper border 

 of the sterno-cephalicus tendon. It is a short but large trunk which is formed 

 by the confluence at the posterior border of the jaw of masseteric and pterygoid 

 veins. The former is commonly connected by an anastomotic branch with the 

 buccinator vein. 



4. The great auriciilar vein (V. auricularis magna) is a satellite of the posterior 

 auricular artery above, but joins the jugular a variable distance below and behind 

 the point of origin of the arterj\ 



5. The occipital vein (V. occipitalis) arises in the fossa atlantis by the union of 

 two radicles. It passes downward and backward on the rectus capitis ventralis 

 major and joins the jugular vein a variable distance in front of the termination of the 

 external maxillary vein. The anterior radicle is the ventral cerebral vein (V. 

 cerebralis ventralis). This is an emissary of the cavernous sinus of the dura mater; 

 it emerges through the foramen lacerum posterius and is connected with a venous 

 plexus in the infratemporal fossa. It receives the condyloid vein (V. condyloidea), 

 which is an emissary of the basilar plexus and the petrosal sinus, and emerges 

 through the hypoglossal foramen.^ The posterior radicle is formed by the con- 

 fluence of muscular and cerebro-spinal branches. The former (Ramus muscularis) 

 comes through the foramen transversarium of the atlas from the muscles of the 

 poll; it anastomoses with the vertebral and deep cervical veins. The latter (Ramus 

 cerebrospinalis) receives emissary veins from the meningeal plexus in the atlas, 

 which emerge through the intervertebral and alar foramina and the foramen of the 

 lateral mass of the atlas. 



6. The external maxillary vein (V. maxillaris externa) arises by radicles which 

 correspond in general to the branches of the artery of like name. It passes down 

 over the cheek along the anterior border of the masseter muscle behind the artery, 

 crossing over the parotid duct, which lies behind the vein lower down. Thus on 

 the ramus and as they turn around its ventral border the artery is in front, the vein 

 in the middle, and the duct posterior. In the mandibular space the vein is ventral 

 to the artery for some distance, then parts company with the artery, runs straight 

 backward along the ventral border of the parotid gland, and opens into the jugular 

 vein at the posterior angle of the gland.^ The chief differences in the tributaries 

 of the vein as compared with the branches of the corresponding artery are as follows: 



The labial veins (Vv. labiales), superior and inferior, are in the substance of the 

 orbicularis oris near the free edges of the lips. The upper one is the larger. They 

 anastomose with the opposite veins. They drain into a venous plexus which is 

 situated in the submucous tissue of the cheek and the buccinator muscle, and from 

 this plexus two veins emerge. The upper one passes back and joins the buccinator 

 vein. The lower one, the common labial vein (V. labialis communis), receives a 

 submental vein from the chin and joins the external maxillary vein. 



Three veins connect with the external maxillary at the anterior border of the 

 masseter. 



1 On account of the existence of this cranial affluent the term cranio-oocipital has been pro- 

 posed for the venous trunk. 



2 The venous angle formed by this junction indicates the position of the thyroid gland. 



