THE DIPLOIC VEINS 



651 



and the deep cervical veins; close to its termination it is sometimes joined by the 

 first intercostal vein. 



The Anterior Vertebral Vein commences in a plexus around the transverse pro- 

 cesses of the upper cervical vertebrae, descends in company with the ascending 

 cervical artery between the Scalenus anterior and Longus capitis muscles, and 

 opens into the terminal part of the vertebral vein. 



VERTEBRAL 



POSTERIOR 



DEEP 



CERVICAL 



POSTERIOR 



EXTERNAL 



JUGULAR 



VERTEBRAL 



ASCENDING 

 CERVICAL 





FIG. 563. The vertebral vein. (Poirier and Charpy.) 



The Deep Cervical Vein (v. cervicalis profunda; posterior vertebral or posterior 

 deep cervical vein) accompanies its artery betw r een the Semispinales capitis and 

 colli. It begins in the suboccipital region by communicating branches from the 

 occipital vein and by small veins from the deep muscles at the back of the neck. 

 It receives tributaries from the plexuses around the spinous processes of the cer- 

 vical vertebrae, and terminates in the lower part of the vertebral vein. 



The Diploic Veins (Venae Diploicas) (Fig. 564). 



The diploic veins occupy channels in the diploe of the cranial bones. They are 

 large and exhibit at irregular intervals pouch-like dilatations; their walls are thin, 

 and formed of endothelium resting upon a layer of elastic tissue. 



So long as the cranial bones are separable from one another, these veins are 

 confined to the particular bones; but when the sutures are obliterated, they unite 

 with each other, and increase in size. They communicate with the meningeal 

 veins and the sinuses of the dura mater, and w r ith the veins of the pericranium. 

 They consist of (1) the frontal, which opens into the supraorbital vein and the 

 superior sagittal sinus; (2) the anterior temporal, which is confined chiefly to the 

 frontal bone, and opens into the sphenoparietal sinus and into one of the deep 

 temporal veins, through an aperture in the great wing of the sphenoid; (3) the 

 posterior temporal, which is situated in the parietal bone, and ends in the transverse 

 sinus, through an aperture at the mastoid angle of the parietal bone or through the 



