892 



NEUROLOGY 



I 



palatine foramen. It is triangular or heart-shaped, of a reddish-gray color, and is 

 situated just below the maxillary nerve as it crosses the fossa. It receives a sensory, 

 a motor, and a sympathetic root. 



Its sensory root is derived from two sphenopalatine branches of the maxillary 

 nerve; their fibers, for the most part, pass directly into the palatine nerves; a few, 

 however, enter the ganglion, constituting its sensory root. Its motor root is probably 

 derived from the nervus intermedius through the greater superficial petrosal nerve 

 and is supposed to consist in part of sympathetic efferent (preganglionic) fibers 

 from the medulla. In the sphenopalatine ganglion they form synapses with neurons 

 whose postganglionic axons, vasodilator and secretory fibers, are distributed with 

 the deep branches of the trigeminal to the mucous membrane of the nose, soft 

 palate, tonsils, uvula, roof of the mouth, upper lip and gums, and to the upper part 

 of the pharynx. Its sympathetic root is derived from the carotid plexus through the 

 deep petrosal nerve. These two nerves join to form the nerve of the pterygoid 

 canal before their entrance into the ganglion. 



Termination of 

 nasopalatine 



nerve 



FIG. 780. The sphenopalatine ganglion and its branches. 



The greater superficial petrosal nerve (n. petrosus superficialis major; large super- 

 ficial petrosal nerve) is given off from the genicular ganglion of the facial nerve; it 

 paSses through the hiatus of the facial canal, enters the cranial cavity, and runs 

 forward beneath the dura mater in a groove on the anterior surface of the petrous 

 portion of the temporal bone. It then enters the cartilaginous substance which 

 fills the foramen lacerum, and joining with the deep petrosal branch forms the 

 nerve of the pterygoid canal. 



The deep petrosal nerve (n. petrosus profundus; large deep petrosal nerve') is given 

 off from the carotid plexus, and runs through the carotid canal lateral to the internal 

 carotid artery. It then enters the cartilaginous substance which fills the foramen 

 lacerum, and joins with the greater superficial petrosal nerve to form the nerve 

 of the pterygoid canal. 



The nerve of the pterygoid canal (n. canalis pterygoidei [Vidii]; Vidian nerve), 



