The Head and Neck. 



253 



nected with the sphenopalatine ganglion. Nasal rami pass 

 to the mucous membrane of the nose, and the nasopalatine nerve 

 enters the nasal region, traversing the surface of the septum and 

 reaching the anterior portion of the palate through the incisive 

 foramina. 



The nerve of the pterygoid canal (n. canalis pterygoidei) is a 

 slender cord which passes backward along the orbital wall from the 

 posterodorsal angle of the gang- 

 lion. It lies on the medial side of 

 the sphenopalatine and infraorbital 

 nerves and on the lateral surface 

 of the palatine bone. Posteriorly 

 it enters the groove representing 

 the pterygoid canal'. 



This nerve is composed of 

 two parts, separated poster- 

 iorly. One of them, the deep 

 petrosal nerve (n. petrosus 

 profundus), is connected with 

 the sympathetic plexus of the 

 internal carotid artery. The 

 other, the great superficial 

 petrosal nerve (n. petrosus 

 superficialis major) enters the 

 skull at the foramen lacerum, 

 passing into the petrosal bone, 

 in the interior of which it is 

 connected with the trunk of 

 the facial. The nerve con- 

 stitutes the motor root of the 

 sphenopalatine ganglion, the 



sensory root being that provided by the sphenopalatine nerve. 

 The sphenopalatine ganglion is one of several representing 

 the sympathetic system in the head, and having motor and 

 sensory roots from the cerebral nerves in addition to their 

 sympathetic connections. The series includes the ciliary 

 ganglion, which lies on the optic nerve, the sphenopalatine 

 ganglion, the otic ganglia, associated with the mandibular 



Fig. 81. Diagram of the parts of the 

 ear in vertical projection. To show the 

 general relations of the structures covered 

 by the dissection. 



p, petrous portion of the petrotympanic 

 bone; t., tympanic portion (bulla tym- 

 pani) . 



c, cochlea; c.s., bony semicircular 

 canals; c.t., tympanic cavity; d.c, 

 cochlear duct; d.e., endolymphatic duct; 

 d.m., dura mater; d.s., semicircular 

 ducts; f.c, cochlear fenestra; f.v., vesti- 

 bular fenestra; i., incus; m, malleus; 

 m.a.e., external acoustic meatus, termin- 

 ating at the tympanic membrane; m.a.i., 

 internal acoustic meatus; s., sacculus; 

 s.e., endolymphatic sac; St., stapes; t.a., 

 auditory tube; tl., utriculus; v, vestibulum; 

 VIII, acoustic nerve. 



