SINUSES OF THE DURA MATER. 



397 



F.o. 112. 



also found upon the arach- 

 noid membrane. These 

 glands, as they are called, 

 consist of small, round, 

 whitish bodies, found in 

 clusters or singly, and 

 varying in number, size, 

 and appearance. 



The inferior longitudi- 

 nal sinus resembles a vein, 

 and receives the veins of 

 the corpus callosum. It 

 ends in the straight sinus. 

 The two lateral sinuses 

 are the largest, and formed 

 by the junction of the lon- 

 gitudinal and straight. 

 They commence at the in- 

 ternal occipital protuber- 

 ance, course outward along 

 the convex border of the 

 tentorium, within the hor- 

 izontal occipital groove, 

 thence along the channel 

 in the mastoid portion of 

 the temporal bone, and finally pass out of the skull at the 

 foramen lacerum posterius to become the internal jugular 

 veins of the neck. 



The vein of Galen corresponds to the rectus or straight 

 sinus which is situated between the laminae at the base of 

 the falx major, where it rests upon the tentorium. It receives 



FIG. 112, A represents the sinuses of the dura-mater, a Superior longitudinal 

 sinus. 6 Inferior longitudinal sinus, both of these sinuses are in the falx cere- 

 bri. c Veins of galen. d Rectus or straight sinus, e Torcular Herophili. 



FIG. 112, B represents the sinuses at the base of the cranium. 1 Opening 

 of superior longitudinal sinus into the torcular Herophili. 2 Left lateral sinus. 

 d Where the jugular vein commences, e Superior petrosal sinus. /Cavern- 

 ous sinus, g Ophthalmic vein, h Transverse sinus, i Circular or coronary 

 sinus of Ridley. 



