THE HEAD AND NECK. 



129 



The Cavernous Sinus. The sinus is located between the apex of the 

 petrous portion of the temporal bone and the sphenoidal fissure. Note that all 

 the nerves you have just seen in the table passing through the sphenoidal 

 fissure also pass through the cavernous sinus. 



The sinus contains the following structures : 



1. The venous blood common to dural sinuses. 



2. The cavernous stage of the internal carotid artery. 



KACH C/M.V/.IA 

 XEIi VE Off ITU 

 KXI'AI'R RE- 

 I'EIVEX A PSU- 

 TEVTIOS III-' 

 MATEH 



FIG. 87. SCHEMATIC. 

 To show the dura mater forming sheaths for the nerves as they leave the cranium. 



3. The sympathetic plexus of nerves on the common carotid artery. 



4. The ophthalmic division of the fifth cranial nerve. 



5. The motor oculi, the third cranial, nerve. 



6. The patheticus, the fourth cranial, nerve. 



7. The abducens, the sixth cranial, nerve. 



Dissection. Remove the dura mater. Take hold of it in the region of the 

 frontal bone, and pull it back. It will come off quite readily. Locate the 



CAVERNOUS SINUS 

 INT.CAROTIO ARTERY - 



Fir,. 88. RELATION OF THE VARIOUS STRUCTURES PASSING THROUGH THE CAVERNOUS SINUS. 



internal carotid artery next to the sphenoid wall of the sinus. The small nerve 

 on the artery is the sixth cranial. You will find the others on the outer wall, 

 from above downward : third, fourth, and fifth. 



The Gasserian Ganglion. Remove in the same way the dura mater from 

 the middle fossa as you did from the anterior, and you will expose the Gasserian 

 ganglion in a depression on the anterior surface of the petrous portion of the 

 temporal bone near the apex. The ganglion lies between two layers of subdural 



