NERVUS TRIGEMINUS. 459 



taL This branch descends a little distance, externally, along 

 the posterior paries of the maxillary sinus, then penetrates into 

 the cavity of the latter. It terminates by filaments, some of 

 which supply the lining membrane of the antrurn; others pass 

 through the little canals leading to the three large grinders, 

 and enter the roots of the latter; others go to the correspond- 

 ing gums. One branch goes along the outer side of the sinus 

 to anastomose with the anterior dental nerve. The posterior 

 dental, before it enters the bone, also detaches a branch of 

 some size, which winds around the tuberosity of the maxillary 

 bone, and is spent upon the buccinator muscle and upon the 

 gums. 



The infra-orbitary nerve afterwards, in its course through 

 the canal, sends off the anterior dental nerves from one or 

 more roots. Some of them detach fibres to the mucous mem- 

 brane of the nose, where it covers the anterior part of the in- 

 ferior turbinated bone. With this exception, they are distri- 

 buted, through their appropriate canals in the bone, to the in- 

 cisor and canine teeth, and to the corresponding gums. The 

 small molar teeth are most frequently supplied by a union of 

 filaments, from the anterior and posterior dental nerves. 



The infra-orbitar nerve, on issuing from the infra-orbitar fo- 

 ramen, is most frequently found already divided into several 

 fasciculi, which may be classed into superior and into inferior. 

 The former, called Palpebral, radiate, externally and internal- 

 ly, into filaments which supply the lower eyelid. One of these 

 filaments^may be traced to the end of the nose, where it anas- 

 tomoses with the internal nasal branch of the ophthalmic ; ano- 

 ther, which terminates about the internal angle of the eye, 

 anastomoses there with the external nasal nerve. Others of 

 its terminating filaments anastomose with the extremities of 

 the facial nerve on the eyelid. The inferior fasciculi are more 

 numerous and large than the superior. They descend upon 

 the face covered by the levator muscles of the upper lip, and 

 from their distribution are called Labial. The most internal 

 of these fasciculi terminate on the skin, the muscles, and the 

 beginning of the mucous membrane of the nose, where they 

 anastomose with the extremities of the internal nasal nerve. 

 The middle fasciculi go to the muscles of the upper lip and the 

 of the latter, and to its mucous glands. The external fas- 



