988 



THE NERVE SYSTEM 



enter the ganglion, constituting its sensor root. Its motor root is derived from the 

 facial nerve through the large superficial petrosal nerve, and its sympathetic 

 root from the carotid plexus, through the large deep petrosal nerveT These two 

 nerves join together before their entrance into the ganglion to form a single nerve. 

 the Vidian. 



The large or great superficial petrosal branch (11. petrosus superficialis major) 

 (Fig. 739) is given off from the geniculate ganglion implanted on the external genu 

 of the facial nerve in the facial canal or aquaeductus Fallopii; it passes through 

 the hiatus canalis facialis, enters the cranial cavity, and runs forward, being 

 contained in a groove on the anterior surface of the petrous portion of the temporal 

 bone, and lies beneath the dura. It then enters the cartilaginous substance which 

 fills in the foramen lacerum medium, and, joining with the large deep petrosal 

 nerve, forms the Vidian nerve. 



Termination of 



nasopalatine 



nerve. 



FIG. 735. The sphenopalatine or Meckel's ganglion and its branches 



The large deep petrosal nerve (n. petrosus profundus) (Fig. 740) is given off 

 from the carotid plexus of the sympathetic upon the internal carotid artery, 

 and runs through the carotid canal on the outer side of the internal carotid artery. 

 It then enters the cartilaginous substance which fills in the foramen lacerum 

 medium, and joins with the large superficial petrosal nerve to form the Vidian, 



The Vidian nerve (n. canalis pterygoidei) (Fig. 735), formed by the junction of 

 the two preceding nerves in the cartilaginous substance which fills in the middle 

 lacerated foramen, passes forward, through the Vidian canal, with the artery of 

 the same name, and is joined by a small ascending nerve branch, the sphenoidal 

 branch, from the otic ganglion. Finally, it enters the sphenomaxillary fossa, and, 

 posterior angle of the sphenopalatine ganglion. 



Branches of Distribution of the Sphenopalatine Ganglion. These are divisible 

 into four groups ascending, which pass to the orbit; descending, to the palate: 

 internal, to the nose; and posterior branches, to the nasopharynx. 



