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 

Fic. 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; u., utriculus; v, vestibulum; 
VIII, acoustic nerve. 
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 
