384 SPECIAL ANATOMY. 



of sinus cavernosus, gives a filament backwards which accompa- 

 nies another of the trochkaris to the tentorium, and divides into 

 three branches, which pass through thefissura orbitalis superior, 

 at different points, into the orbita. Position : below n. trochlearis, 

 external to n. oculo-motorius and abducens. Branches from with- 

 out inwards are: N. lacrymalis, n.frontalis, n. nasalis. 



1. N. frontalis, the frontal nerve, the continuation of ophthal- 

 micus, and its thickest branch, passes horizontally forwards under 

 the periorbita and obliquely above the kv.palpebr., sends frequent- 

 ly a small branch which passes over the m. obliq. sup., and under 

 the trochlea, out of the orbita, and into the superior eyelid. In front 

 it divides into : 



a. N. supraorbitalis, the external larger branch, which passes 

 through foram. supraorbitale, out of the orbita, sends nume- 

 rous branches downwards to the superior lids (one of which 

 anastomoses with n.facialis beneath n. orbicularis), two others 

 upwards to the skin of the forehead, which may be followed 

 as far as the lambdoidal suture, but only supply the skin and 

 periosteum. A smaller branch passes through a small fora- 

 men in the foram. supraorbit. into a canal on the frontal bone, 

 and to the skin of the forehead on the tuber frontak. 



b. N. supratrochlearis, the smaller internal branch, passes out 

 between for. supraorbit. and (above) the trochlea of m. obliq. 

 sup., and divides into superior branches for the top of the 

 forehead, and into inferior for the upper lid and back of the 

 nose, where it anastomoses with n. nasalis. Sometimes two 

 nn. supratrochl. are present. 



2. JV. nasalis s. naso-ciliaris passes between ram. super, and 

 infer, of oculo-motor., inwards and forwards, obliquely over n. 

 options, beneath m. rectus and obliq. super, to the internal wall of 

 the orbita, and divides at the superior border of m. rectus intern. 

 into n. ethmoidalis and infratrochlearis. Before this one or several 

 nervi ciliares pass off from it, and the 



a. Radix longa ad ganglion ciliare, a minute, sometimes double 

 filament, which separates even in the cranial cavity (in the 

 sinus cavern.), where also a grayish filament (radix media) 

 from plexus carot. n. sympath. is applied, and accompanies it 

 to the posterior angle of the 



Ganglion ciliare s. ophthalmicum. This lenticular, flat, 

 grayish-red ganglion lies in a considerable quantity of fat 

 on the outer side of n. opticus, two to three lines distant 

 from the optic foramen, beneath art. ophthalmica. The 

 radix brevis from oculo-motorius enters at its posterior in- 



