642 Mu. c. n. o'donoghue on tue 



of the brain, outwards, and around the posterior face of the optic 

 lobes to the ventral side of the brain. Here it goes forward and 

 leaves the skull by the foramen for the trigeminal nerve. Out- 

 side the skull it bends sharply backwards and joins the lateral 

 cephalic vein as the latter reaches the internal carotid ai'teiy. 

 The last part of this vessel outside the skull is a secondary con- 

 nection (V. cerebralis media secundaria, Grosser and Brezina) 

 developed between the median cerebral vein, which originally 

 opened into the internal jugular, and the lateral cephalic vein. 

 During its course it receives : — 



A. The Dorsal Cephalic Vein (V. capitis dorsalis, Bruner), which 



arises from its dorsal side within the skull and passes 

 outward through a special foramen. It runs backwards 

 between the pro-otic and squamosal bones, receiving one 

 or two cutaneous veins, and then bends laterally and enters 

 the lateral cephalic vein. 



B. The Secondary Anterior Cerebral Vein, which runs on the 



floor of the cranium and joins it to the orbital sinus {vide 

 sup)ra). 



C. The Palato-cerebral Vein, which connects it with the oblique 



palatine vein {vide siopra). According to Bruner there 

 is a,lso an external secondaiy anastomosis with the anterior 

 cerebral vein, as well as the internal one described above. 

 I have been unable to find this vein by dissection. 



III. A large vein from the parotid gland and the muscles of 

 the head, which closely accompanies the maxillary artery and 

 enters the lateral cephalic vein close to the place where the 

 maxillary artery leaves the internal carotid. 



lY. A Dorsal Cejjhalic Vein {vide sup7-a), which joins it to the 

 median cerebral vein. 



V. The Posterior Cerebral Vein (Y. cerebralis posterior, Bruner), 

 which runs from the end of the longitudinal cei-ebral vein a little 

 behind the posterior end of the optic lobes obliquely outwards 

 over the medulla oblongata and leaves the skull by the foramen 

 magnum. Just before leaving the cranium it gives off a S2nnal 

 vein Avhich runs caudally on the ventral side of the spinal cord, 

 where it unites with the similar vessel from the other side. 



YI. One well-marked and several smaller veins from the 

 muscles of the posterior end of the skull. 



YII. A Cervical vein which returns blood from the muscles of 

 the neck. 



The Longitudinal Cerebral Vein ( Y. longitudinis cerebri, Bruner) 

 is a vessel running backwards along the mid-dorsal aspect of the 

 brain from between the olfactory lobes. At the postei'ioi' end of 

 the optic lobes it gives off the median cerebral veins, and a short 

 distance further back divides to foi-m the posterior cei'ebral 

 veins. 



