OPHTHALMIC. 617 



The supraorbital branch passes forwards through the supraorbital foramen, 

 and gives off, in this situation, palpebral filaments to the upper eyelid. It then 

 ascends upon the forehead, and terminates in muscular, cutaneous, and pen- 

 cranial branches. The muscular branches supply the Corrugator Supercilii, 

 Occipito-frontalis, and Orbicularis Palpebrarum, furnishing these muscles with 

 common sensation, and joining in the substance of the latter muscle with the 

 facial nerve. The cutaneous branches, two in number, an inner and an outer, 

 supply the integument of the cranium as far back as the occiput. They are at 

 first situated beneath the Occipito-Yrontalis, the inner branch perforating the 

 frontal portion of the muscle, the outer branch its tendinous aponeurosis. The 

 pericranial branches are distributed to the pericranium over the frontal and 

 parietal bones. They are derived from the cutaneous branches whilst beneath 

 the muscle. 



The Nasal nerve is intermediate in size between the frontal and lachrymal, 

 and more deeply placed than the other branches of the ophthalmic. It enters 

 the orbit between the two heads of the External Eectus, and passes obliquely 

 inwards across the optic nerve, beneath the Levator Palpebras and Superior 

 Kectus muscles, to the inner wall of the orbit, where it enters the anterior 

 ethmoidal foramen, immediately below the Superior Oblique. It then enters 

 the cavity of the cranium, traverses a shallow groove on the front of the cribri- 

 form plate of the ethmoid bone, and passes down, through the slit by the side 

 of the crista galli, into the nose, where it divides into two branches, an internal 

 and an external. The internal branch supplies the mucous membrane near the 

 fore part of the septum of the nose. The external branch descends in a groove 

 on the inner surface of the nasal bone, and supplies a few filaments to the 

 mucous membrane covering the fore part of the outer wall of the nares as far 

 as the inferior spongy bone; it then leaves the cavity of the nose, between the 

 lower border of the nasal bone and the upper lateral cartilage of the nose, and, 

 passing down beneath the Compressor Nasi, supplies the integument of the ala 

 and tip of the nose, joining with the facial nerve. 



The branches of the nasal nerve are, the ganglionic, ciliary, and infratrochlear. 



The ganglionic is a long, slender branch, about half an inch in length, which 

 usually arises from the nasal, between the two heads of the external rectus. It 

 passes forwards on the outer side of the optic nerve, and enters the superior 

 and posterior angle of the ciliary ganglion, forming its superior, or long root. 

 It is sometimes joined by a filament from the cavernous plexus of the sympa- 

 thetic, or from the superior division of the third nerve. 



The long ciliary nerves, two or three in number, are given off from the nasal 

 as it crosses the optic nerve. They join the short ciliary nerves from the ciliary 

 ganglion, pierce the posterior part of the sclerotic, and, running forwards 

 between it and the choroid, are distributed to the ciliary muscle and iris. 



The infratrochlear branch is given off just as the nasal nerve passes through 

 the anterior ethmoidal foramen. It runs forwards along the upper border of 

 the Internal Rectus, and is joined, beneath the pulley of the Superior Oblique, 

 by a filament from the supratrochlear nerve. It then passes to the inner angle 

 of the eye, and supplies the Orbicularis Palpebrarum, the integument of the 

 eyelids, and side of the nose, the conjunctiva, lachrymal sac, and caruncula 

 lachrymalis. 



Connected with the three divisions of the fifth nerve are four small Ganglia, 

 which form the whole of the cephalic portion of the sympathetic. With the 

 first division is connected the ophthalmic ganglion ; with the second division, 

 the spheno-palatine, or Meckel's ganglion; and with the third, the otic and sub- 

 maxillary ganglia. All the four receive sensitive filaments from the fifth, and 

 motor and sympathetic filaments from various sources; these filaments are 

 called the roots of the ganglia. The ganglia are also connected with each other, 

 and with the cervical portion of the sympathetic. 



