THE MAXILLARY NERVE 937 



the naso-ciliary nerve itself receives numerous sympathetic (secretory' and vaso- 

 motor) fibres. 



Its several branches are: (i) The long root of the ciliary ganglion which is given off at the 

 superior orbital (sphenoidal) fissure. It is a slender filament which runs forward on the lateral 

 side of the optic nerve to the superior and posterior part of the ciliary ganglion (fig. 734). 



(ii) The long ciliary nerves, usually two in number, which arise from the naso-ciliary nerve 

 as the latter is crossing above the optic nerve. They run forward, on the medial side of the optic 

 nerve, pierce the sclerotic, and are distributed with the lower set of short cihary nerves (fig. 734). 

 The long root of the cihary ganglion and the long cihary nerves carry sensory fibres which 

 belong to the naso-ciliary nerve proper, most of which merely pass through the ganglion, and 

 it carries sympathetic fibres, added to it, most of which may terminate about the cell-bodies of 

 the ganglion. 



(iii) The posterior ethmoidal (spheno-ethmoidal) branch springs from the posterior border 

 of the naso-ciliary nerve near the upper border of the rectus medialis. It passes through the 

 posterior ethmoidal canal and is distributed to the mucous membrane of the posterior ethmoidal 

 cells and the sphenoidal sinus. 



(iv) The infratrochlear nerve passes forward between the obhquus superior and the rectus' 

 medialis, and under the pulley of the former muscle divides into two branches: — The superior 

 palpebral branch helps to supply the eyelids with sensory fibres and usuallj' anastomoses with 

 the supratrochlear nerve. The inferior palpebral branch is distributed to the lacrimal sac, 

 the conjunctiva and skin of the medial part of the upper eyehd, the caruncle, and the skin of 

 the upjier part of the side of the nose. 



(v) The anterior ethmoidal (distal part of the nasal) nerve, passing forward and medial- 

 ward between the obliquus superior and the rectus medialis, leaves the orbit through the anterior 

 ethmoidal foramen, accompanied by the anterior ethmoidal vessels, and enters into the anterior 

 fossa of the cranium (fig. 7.34). It then crosses the lamina cribrosa of the ethmoid, lying outside 

 the dura mater, which separates it from the olfactory bulb, and descends into the nasal fossa 

 through the ethmoidal fissure, a slit-like aperture at the side of the crista galli. In the sub- 

 mucosa of the nasal fossa it terminates by dividing into two sets of anterior nasal branches: 

 the internal nasal branches and the external nasal branch (fig. 732). 



The internal nasal branches divide into the medial nasal branches (the septal branches of 

 the nasal nerve), which run downward and forward on the upper and front part of the septum, 

 and the lateral nasal branches (the external terminal branch of the nasal nerve), which give 

 twigs to the anterior extremities of the superior and middle nasal conchse (turbinated bones), 

 and to the mucous membrane of the lateral wall of the nose (fig. 732). 



The external nasal branch (the anterior terminal branch of the nasal nerve) runs do-^vnward 

 in a groove on the inner surface of the nasal bone. It pierces the waU of the nose between the 

 nasal bone and the upper lateral cartilage, and supphes the integument of the lower part of 

 the dorsum of the nose as far as the tip. 



(2) The ]VL\xillary Nerve or Second Division of the Trigeminus 



The maxillary nerve is entirely sensory in function and it is intermediate in 

 size between the ophthalmic and mandibular nerves. 



It springs from the middle of the anterior border of the semilunar (Gasserian) 

 -ganglion and runs forward in the lower and outer part of the lateral wall of the 

 cavernous sinus (fig. 735). Leaving the middle fossa of the cranium, by passing 

 through the foramen rotundum, it enters the pterygo-palatine (spheno-maxillary) 

 fossa (fig. 734), where it is joined by twigs with the spheno-palatine ganglion; 

 then, changing its name, it passes forward, as the infra-orbital nerve, through the 

 inferior orbital (spheno-maxillary) fissure into the infra-orbital sulcus in the floor 

 of the orbit; continuing forward it traverses the infra-orbital canal accompanied 

 by the infra-orbital arterj^, and appears in the face, beneath the levator labii 

 superioris (quadratus) and above the levator anguli oris (caninus) where it divides 

 into four sets of terminal branches which anastomose more or less freely with 

 branches of the facial nerve to form the infra-orbital plexus. 



Branches. — The branches of the maxillary nerve are — (a) branches given off 

 in the middle fossa of the cranium; (6) branches given off in the pterygo-palatine 

 (spheno-maxillary) fossa; (c) branches given off in the infra-orbital sulcus and 

 '•anal; and (d) terminal branches. 



(a) The middle (recurrent) meningeal branch, given off in the middle fossa 

 of the cranium, breaks up into numerous branches which supply the dura mater 

 with sensory fibres, reinforce the sj^mpathetic plexus on the middle meningeal 

 artery, and anastomose with the spinous nerve (the recurrent branch of the man- 

 dibular nerve). 



(6) The branches given off in the pterygo-palatine (spheno-maxillary) fossa 

 are the spheno-palatine nerves, the zygomatic branch of the maxillary nerve, and 

 the posterior superior alveolar nerves. 



