THE EXTERNAL JUGULAR VEIN 



647 



veins. It contains a pair of valves about 2.5 to 5 cm. (1 to 2 in.) above the clavicle, and a 

 second pair where it enters the subclavian vein. Neither of these valves is sufficient to prevent 

 the blood from regurgitating, or injections from passing from the larger vein into the external 

 jugular. 



Tributaries and communications. — These include; — (a) The posterior auricular 

 vein; (b) the occipital vein; (c) a branch of communication with the posterior fa- 

 cial vein; (d) the posterior external jugular vein; (e) the transverse scapular vein; 

 and (f) the anterior jugular vein. 



(a) The posterior auricular vein [v. auricularis posterior] begins in a venous plexus on the 

 posterior part of the parietal bone. This plexus communicates with the vein of the opposite 

 side across the sagittal suture, and with the posterior branch of the superficial temporal vein 

 in front, and with the occipital vein behind. It descends over the back part of the parietal 

 bone and the mastoid process of the temporal bone, lying with its artery behind the ear, and 

 joins a branch from the posterior facial vein to form the external jugular. 



Fig. 512. — The Veins op the Face. (After Toldt, "Atlas of Human Anatomy," Rebman, 



London and New York.) 



Deep temporal veins 



Infraorbital artery and vein 



Dura mater ! ] 



' I Frontal diploic vein 



Lateral lacuna of the superior sagittal sinus 

 Sphenoparietal sinus 



\ 



Frontal vein 

 / 



Naso-frontal 

 vein 



External nasal 

 veins 



Anasto- 

 ^^ mosing 

 C* facial 

 < vein 



Jugular 

 vein 



Middle 

 temporal 



vein 

 Articular man 

 dibular veins 



Superficial '' 

 temporal arterj f 

 Pterygoid 

 plexus 

 Internal 

 maxillary artery 

 Inferior 

 alveolar nerve 

 Posterior facial vein ■'' 

 Inferior alveolar artery 

 and vein 



f Postenor 

 external 

 Internal -' '" 



Common facial vein-- 



— ^ External maxil- 

 lary artery 



-.^^ Digastric 



muscle 

 Veins accompany- 

 ing the hypoglossal 

 nerve 

 Lingual artery 

 Superior laryngeal artery 

 and vein 



Superior thyreoid artery and vein 



(b) The occipital vein [v. occipitalis] begins at the back of the skull in a venous plexus 

 which anastomoses with the posterior auricular and the posterior branch of the superficial 

 temporal veins. It passes downward over the occipital bone, and usually perforates the 

 trapezius with the occipital artery, to join a plexus drained by the deep crevical and vertebral 

 veins. It also communicates with the posterior auricular, and in many cases this forms the 

 chief path of drainage. One of its branches, usually the most lateral, receives a mastoid em- 

 issary vein [emissarium mastoideum] which issues through the mastoid foramen of the tem- 

 poral bone, and in this way forms a communication with the transverse sinus. 



(c) The branch of communication with the posterior facial vein occurs a short distance below 

 the point at which the posterior facial receives the internal maxillary vein. It is very constant 

 and is placed immediately behind the angle of the mandible. Through it the external jugular 



