712 THE NERVES. 



these (Fig. 335, 3') traverses the ocular sheath behind the orbital process, 

 and places itself, from before to behind, on the external surface of the zygo- 

 matic 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 integu- 

 ments of the ear. 



Palpebko-nasal Nbkve (Fig. 335, 2). — This describes a curve, like 

 the ophthahnic 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 (infratrocJilear) 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 (Fig. 336, 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 ophthalmic branch already described as a collateral division of this 

 trunk. 



Eemarkable for its volume, and its prismatic and funicular shape, the 

 superior maxillary nerve proceeds from the inner and upper section of the 

 semilunar ganglion, and at first occupies the fissure on the internal face 

 of the sphenoid bone, without the cavernous sinus, and is covered at this 

 point by the dura mater. After sending the' ophthalmic branch into the 

 smallest of the great suprasphenoidal conduits — the great sphenoidal fissurej 

 it enters the most spacious of these openings — the foramen rotundiim, axiives 

 in the orbital hiatus beneath the sheath of the eye, and, with the internal 

 maxillary artery, passes along the space filled with fat which separates that 

 hiatus from the origin of the supramaxillo-dental (infra-orbital) canal, 

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

 in a number of branches named the infra-orbital ramuscules (or pes anserinus, 

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



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

 among which may be more particularly distinguished : 



1. An orhital branch. 



2. The great or anterior palatine nerve. 



3. The stapTiylin or posterior palatine nerve. 

 i. The nasal or spheno-palatine nerve. 



5. The dental nerves. 



In addition to which are described : 



6. The infra-orbital, or terminal branches of the superior maxillary 

 nerve. 



1. Orbital Branch (Fig. 335, 13).— This ramuscule arises in the inte- 

 rior of the suprasphenoidal canal, and enters the ocular sheath with 

 the divisions of the ophthalmic branch. It almost immediately breaks up 

 into two or three very slender filaments, which ascend to the temporal angle 

 of the eye, passing between the fibrous lining of the orbit and the outer 

 surface of the motor muscles of the eye, and are distributed to the eyelids 

 and neighbouring integuments. 



2. Great or Anteeioe Palatine Nerve (Fig. 148, 3), — It arises 



