816 THE NERVES. 



3. The nasal or palpehro-nasal nerve. 



1. Frontal or Supra-orbital Nerve (Fig. 450, 4). — This is a flat, volu- 

 minous branch placed on the inner wall of the ocular sheath, and proceeding 

 nearly parallel with the great oblique muscle of the eye to the supra-orbital fora- 

 men, into which it passes along with the artery of the same name. Undivided 

 before its entrance into this orifice, immediately after its exit from it, it separates 

 into several ramuscules, which meet the anterior auricular nerve, and are expended 

 in the skin of the forehead and upper eyelid. 



2. Lachrymal Nerve (Fig. 450, 3). — This is composed of several filaments, 

 which ascend between the ocular sheath and the elevator muscle of the eyelid and 

 superior rectus, to enter the lachrymal gland. One of these (Fig. 450, 3') 

 traverses the occular sheath behind the orbital process, and places itself — from 

 before to behind — on the external surface of the zygomatic process, where it 

 divides into a number of ramuscules, some of which mix with those of the anterior 

 auricular nerve to form the plexus of that name, while the others pass directly into 

 the anterior muscles and integuments of the ear. 



3. Nasal or Palpebro-nasal Nerve (Fig. 450, 2). — This describes a curve, 

 like the ophthalmic artery, and passes with that vessel into the cranium by the 

 orbital foramen. After coursing through the ethmoidal fissure that lodges the 

 artery, it traverses the cribriform plate, and divides into two filaments — an 

 internal and external, which ramify in the pituitary membrane on both sides of 

 the nasal fossa. Before entering the orbital foramen, this nerve gives off a long 

 branch (infra-trochlear) that glides over the floor of the orbit, to reach the nasal 

 angle of the eye, where it is distributed to the lachrymal apparatus lodged there, 

 as well as to the lower eyelid ; it also detaches a long filament to the membrana 

 nictitans and the sensitive roots of the ophthalmic ganglion, which will be noticed 

 hereafter. 



B. Superior Maxillary Nerve (Figs. 425, 19 ; 453, 15). — This nerve is 

 the real continuation of the superior trunk given off by the Gasserian ganglion, 

 where we will begin to follow it to its termination, examining briefly the ophthal- 

 mic branch already described as a collateral division of this trunk. 



Remarkable for its volume, and its prismatic and funicular shape, the superior 

 maxillary nerve proceeds from the inner and upper section of the semilunar gang- 

 lion, and at first occupies the fissure on the internal face of the sphenoid bone, 

 outside the cavernous sinus, and is covered at this point by the dura mater. 

 After sending the ophthalmic branch into the smallest of the great supra- 

 sphenoidal conduits — the great sphenoidal fissure — it enters the most spacious of 

 these openings — the foramen rotundum — arrives in the orbital hiatus beneath the 

 ocular sheath, and, with the internal maxillary artery, passes along the space filled 

 with fat which separates that hiatus from the origin of the infra-orbital foramen, 

 which it follows to its external orifice on the face. There it terminates in a 

 number of branches named the infra-orhital ramuscules (or pes anserinus, from 

 their resemblance to the claws of a goose's foot). 



In its course, this nerve gives off a large number of collateral divisions, among 

 which may be more particularly distinguished : 



1. An orbital branch. 



2. The great or anterior palatine nerve. 



3. The staphyline or posterior palatine nerve, 



4. The nasal or spheno-palatine nerve. 



5. The dental nerves. 



