THE HEAD AND NECK 1077 



time becoming separated and assuming a plexiform arrange- 

 ment. Internally the ganglion is intimately related to the back 

 part of the cavernous sinus and the internal carotid artery at the 

 foramen lacerum medium, and on this aspect it receives delicate 

 filaments from the carotid sympathetic plexus. The motor root of 

 the fifth nerve, small in size, lies in close contact with the deep 

 surface of the ganglion ; but there is no blending of the two sets of 

 fibres, the motor root passing independently in an out\vard direction 

 to the foramen ovale. The great superficial petrosal nerve, on its 

 way to the foramen lacerum medium, passes beneath the ganglion. 



The ganglion contains cells similar to those of a spinal ganglion, and 

 it receives its blood from the middle and small meningeal arteries. 



Branches. — ^The branches of the ganglion arise from its anterior 

 convex aspect, and are known as divisions. They are as follows : 

 the first or ophthalmic division ; the second or superior maxillary 

 division ; and the third or inferior maxillary division. The oph- 

 thalmic and superior maxillary nerves are entirely sensory, but the 

 inferior maxillary nerve, being joined by the motor root, is both 

 sensory and motor. 



The first division of the fifth nerve, or the ophthalmic nerve, is the 

 smallest of the three branches of the ganglion. It passes forwards 

 in the outer wall of the cavernous sinus, where it lies below the 

 fourth ner\'e. On approaching the sphenoidal fissure it parts with 

 its chief branches, in the following order fro.m behind forsvards : 

 (i) nasal, (2) lachrymal, and (3) frontal, the last-named representing 

 the continuation of the nerve. All these three branches enter the 

 orbit through the sphenoidal fissure. As the ophthalmic nerve 

 passes forwards it receives a communicating branch from the 

 cavernous sympathetic plexus, and it furnishes a recurrent men- 

 ingeal branch to the tentorium cerebelli. It also communicates 

 with each of the third, fourth, and sixth nerves. 



The second division of the fifth, or the superior maxillary nerve, 

 passes horizontally fonvards for a short distance in the lower part 

 of the outer wall of the cavernous sinus, and it leaves the cranial 

 cavity through the foramen rotundum, which leads to the spheno- 

 maxillary fossa. Before leaving the cranial cavity it furnishes a 

 delicate recurrent meningeal branch to the dura mater of the middle 

 fossa. 



The third division of the fifth, or the inferior maxillary nerve, is 

 the largest of the three branches of the ganglion. It passes down- 

 wards to the foramen ovale, through which it leaves the cranial 

 cavity, and so enters the zygomatic fossa. It is accompanied by 

 the motor root of the fifth nerve, which joins it as it passes 

 through the foramen ovale. The recurrent meningeal branch of 

 the inferior maxillary nerxe is not given off until after the parent 

 trunk has issued through the foramen ovale, and it enters the cranial 

 cavity through the foramen spinosum, in company with the middle 

 meningeal artery. It then divides into t\vo offsets, one of which 

 supplies the dura mater over the great wing of the sphenoid bone, 



