TRIGEMINAL NERVE 205 



5. The Trig-eminal nerve arises from the outer surface of the 

 pons varolii, and passes forward on the base of the skull to the 

 apex of the petrous portion of the temporal bone. There it 

 divides into three trunks : 



(1) Ophthalmic entirely sensory. 



(2) Superior maxillary entirely sensory. 



(3) Inferior maxillary sensory and motor. 



(1) The Ophthalmic division passes through the sphenoidal 

 fissure and divides into three branches (a) lachrymal, (6) 

 frontal, and (c) nasal. The lachrymal nerve passes along the 

 outer side of the orbit and supplies the lachrymal gland, the 

 conjunctiva and skin of the outer corner of the eye. The 



frontal nerve passes forwards in the upper part of the orbit, 

 and divides into the supraorbital and supratrochlear nerves, 

 which pass through the supraorbital notch and inner corner 

 of the eye respectively, and supply the skin of the forehead 

 and scalp, the supraorbital nerve reaching as far back as the 

 vertex. The nasal nerve enters the nose to supply the mucous 

 membrane, and sends an external branch to supply the skin of 

 the lower part of the nose. 



(2) The Superior Maxillary division passes through the fora- 

 men rotundum in the root of the pterygoid process, passes 

 through the orbit, and emerges on the face through the infra- 

 orbital foramen. Before reaching the face the nerve gives off 

 three dental branches for the supply of the upper teeth, and 

 two branches, the temporal and malar respectively, which emerge 

 from foramina in the malar bone, and supply the skin over that 

 bone and the fore-part of the temple. The infraorbital nerve 

 itself divides into numerous branches, which are arranged in 

 three sets palpebral for the skin of the lower eyelid, nasal 

 for the skin on the side of the nose, and labial for the skin of 

 the upper lip. 



(3) The Inferior Maxillary nerve passes through the foramen 

 ovale in the base of the skull and enters the pterygoid region ; 

 it gives off branches to supply the muscles of mastication 

 viz., temporal, masseter, internal and external pterygoid, and 

 buccinator. It then gives off five named branches (a) the 



