

THE TRIGEMINAL NERVE 



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Its roots are three in number, and enter its posterior border. One, the long 

 or sensory root, is derived from the nasociliary nerve, and joins its postero-superior 

 angle. The second, the short or motor root, is a thick nerve (occasionally divided 

 into two parts) derived from the branch of the oculomotor nerve to the Obliquus 

 inferior, and connected with the postero-inferior angle of the ganglion. The motor 

 root is supposed to contain sympathetic efferent fibers (preganglionic fibers) from 

 the nucleus of the third nerve in the mid-brain to the ciliary ganglion where they 

 form synapses with neurons whose fibers (postganglionic) pass to the Ciliary muscle 

 and to Sphincter muscle of the pupil. The third, the sympathetic root, is a slender 

 filament from the cavernous plexus of the sympathetic; it is frequently blended 

 with the long root. According to Tiedemann, the ciliary ganglion receives a twig 

 of communication from the sphenopalatine ganglion. 



Its branches are the short ciliary nerves. These are delicate filaments, from six 

 to ten in number, which arise from the forepart of the ganglion in tw r o bundles 

 connected with its superior and inferior angles; the lower bundle is the larger. 

 They run forward with the ciliary arteries in a wavy course, one set above and the 

 other below the optic nerve, and are accompanied by the long ciliary nerves from 

 the nasociliary. They pierce the sclera at the back part of the bulb of the eye, pass 

 forward in delicate grooves on the inner surface of the sclera, and are distributed 

 to the Ciliaris muscle, iris, and cornea. Tiedemann has described a small branch 

 as penetrating the optic nerve with the arteria centralis retinae. 



The Maxillary Nerve (n. maxillaris; superior maxillary nerve) (Fig. 778), or 

 second division of the trigeminal, is a sensory nerve. It is intermediate, both in 

 position and size, between the ophthalmic and mandibular. It begins at the middle 

 of the semilunar ganglion as a flattened plexiform band, and, passing horizontally 

 forward, it leaves the skull through the foramen rotundum, where it becomes more 

 cylindrical in form, and firmer in texture. It then crosses the pterygopalatine 

 fossa, inclines lateralward on the back of the maxilla, and enters the orbit through 

 the inferior orbital fissure; it traverses the infraorbital groove and canal in the 

 floor of the orbit, and appears upon the face at the infraorbital foramen. 1 At 

 its termination, the nerve lies beneath the Quadratus labii superioris, and divides 

 into a leash of branches which spread out upon the side of the nose, the lower 

 eyelid, and the upper lip, joining with filaments of the facial nerve. 



Branches. Its branches may be divided into four groups, according as they are 

 given off in the cranium, in the pterygopalatine fossa, in the infraorbital canal, or 

 on the face. 



In the Cranium 



In the Pterygopalatine Fossa 



In the Infraorbital Canal . 

 On the Face 



Middle meningeal. 

 [ Zygomatic. 

 < Sphenopalatine. 

 [ Posterior superior alveolar. 

 J Anterior superior alveolar. 

 I Middle superior alveolar. 

 [ Inferior palpebral. 

 \ External nasal. 

 { Superior labial. 



The Middle Meningeal Nerve (n. meningeus medius; meningeal or dural branch) is 

 given off from the maxillary nerve directly after its origin from the semilunar 

 ganglion; it accompanies the middle meningeal artery and supplies the dura mater. 



The Zygomatic Nerve (n. zygomaticus; temporomalar nerve; orbital nerve) arises 

 in the pterygopalatine fossa, enters the orbit by the inferior orbital fissure, 

 and divides at the back of that cavity into two branches, zygomaticotemporal and 

 zygomaticofacial. 





1 After it enters the infraorbital canal, the nerve is frequently called the infraorbital. 



