354 THE EYEBROWS. 



The external or proper frontal branch, called also supra- 

 orbital, ascends on the forehead through the supra-orbital 

 notch or foramen, and divides into numerous filaments 

 supplying the muscles and scalp in this region, and com- 

 municating with its fellow of the opposite side and with 

 the facial and occipital nerves. 



The nasal branch separates from the ophthalmic in the 

 cavernous sinus, and entering the orbit between the two 

 heads of the external rectus, proceeds inward and forward 

 along the inner surface of the orbit, below the superior 

 oblique muscle, to the anterior sethmoidal foramen, through 

 which it passes into the cranium upon the cribriform plate 

 of the aethmoid bone, and then descends through this plate 

 by the side of the crista galli, into the nose, where it is 

 distributed upon the septum and posterior surface of the 

 nasal bones, as far as the tip of the nose. 



The nasal nerve gives off, in its course, a branch which 

 goes on the outer side of the optic nerve, to the ophthalmic 

 ganglion ; also two other branches, termed ciliary nerves, 

 which do not connect with the ganglion, but go directly 

 into the ball of the eye, through the sclerotica, along with 

 the rest of the ciliary nerves. It also sends off the infra 

 trochlear branch, which passes below the pulley of the 

 superior oblique, supplying the lachrymal ducts, sac, and 

 caruncula lachrymalis communicates with the superior 

 trochlear nerve, and is finally distributed to the side and 

 dorsum of the nose. 



The Function of all these branches of the ophthalmic, is 

 to give common sensibility, or general feeling to all the 

 parts to which they are distributed. 



The superior and inferior maxillary nerves, forming the 

 second and third divisions of the fifth, will be found de- 

 scribed under the head of nerves of the passive and active 

 organs of mastication, which see. The arteries supplying 

 the muscles come from the ophthalmic. 



The eyebrows (supercilia) form the upper boundary of 

 the orbit, and consist of a quantity of sub-cutaneous cellu- 

 lar and adipose structure, with the corrugatores supercilii 



