GANGLIA OF THE FIFTH NERVE. 551 



which crosses the internal maxillary artery. The chorda tympani also Joins it 

 at nn acute angle in this situation. The nerve then passes between the Internal 

 pterygoid muscle and the inner side of the ram us of the jaw, and crosses obliquely 

 to the side of the tongue over the Superior constrictor muscle of the pharynx, and 

 between the Stylo-glossus muscle and deep part of the submaxillary gland ; the 

 nerve lastly runs across Wharton's duct, and along the side of the tongue to its 

 apex, being covered by the mucous membrane of the mouth. 



Its brandies of communication are with the submaxillary ganglion and hypo- 

 glossal nerve. The branches to the submaxillary ganglion are two or three in 

 number ; those connected with the hypoglossal nerve form a plexus at the anterior 

 margin of the Hyo-glossus muscle. 



Its branches of distribution are few in number. They supply the mucous mem- 

 brane of the mouth, the gums, the sublingual gland, the conical and fungiform 

 papilhe and mucous membrane of the tongue, the terminal filaments anastomosing 

 at the tip of this organ with the hypoglossal nerve. 



The INFERIOR DENTAL is the largest of the three branches of the inferior 

 maxillary nerve. It passes downwards with the inferior dental artery, at first 

 beneath the External pterygoid muscle, and then between the internal lateral 

 ligament and the ramus of the jaw to the dental foramen. It then passes forwards 

 in the dental canal in the inferior maxillary bone, lying beneath the teeth, as far 

 as the mental foramen, where it divides into two terminal branches, incisor and 

 mental. The incisor branch is continued onwards within the bone to the middle 

 line, and supplies the canine and incisor teeth. The mental branch emerges from 

 the bone at the mental foramen, and divides beneath the Depressor anguli oris 

 into an external branch, which supplies this muscle, the Orbicularis oris, and the 

 integument, communicating with the facial nerve ; and an inner branch, which 

 ascends to the lower lip beneath the Quadratus menti and supplies this muscle and 

 the mucous membrane and integument of the lip, communicating with the facial 

 nerve. ' 



The branches of the inferior dental are the mylo-hyoid and dental. 



The Mylo-hyoid is divided from the inferior dental just as that nerve is about 

 to enter the dental foramen. It descends in a groove on the inner surface of the 

 ramus of the jaw, in which it is retained by a process of fibrous membrane. It 

 supplies the cutaneous surface of the Mylo-hyoid muscle, and the anterior belly 

 of the Digastric, occasionally sending one or two filaments to the submaxillary 

 gland. 



The Dental branches supply the molar and bicuspid teeth. They correspond in 

 number to the fangs of those teeth ; each nerve entering the orifice at the point 

 of the fang, and supplying the pulp of the tooth. 



Two small ganglia are connected with the inferior maxillary nerve : the otic, 

 with the trunk of the nerve ; and the submaxillary, with its lingual branch, the 

 gustatory. 



GANGLIA CONNECTED WITH THE FIFTH NERVE. 



Connected with the three divisions of the fifth nerve are four small ganglia, 

 which form the whole of the cephalic portion of the sympathetic. With the first 

 division is connected the ophthalmic ganglion ; with the second division, the spheno- 

 palatine or Meckel's ganglion ; and with the third, the otic and submaxillary 

 ganglia. These ganglia receive sensitive filaments from the fifth, and motor and 

 sympathetic filaments from various sources ; these filaments are called the roots of 

 the ganglia. The ganglia are also connected with each other, and with the 

 cervical portion of the sympathetic. 



(1.) OPHTHALMIC OR CILIARY GANGLION. 



The OPHTHALMIC, LENTICULAR or CILIARY GANGLION (fig. 276) is a small, 

 quadrangular, flattened ganglion, of a reddish-gray color, and about the size of a 



