598 THE CRANIAL NERVES. 



orbicularis palpebrarum and occipito-frontalis muscles, furnishing twigs to 

 these muscles and the corrugator supercilii, and, after ascending on the fore- 

 head, ramifies in the integument. 



6. The supraorbital branch (external frontal) passes through the supra- 

 orbital notch to the forehead, and ends in muscular, cutaneous, and peri- 

 cranial branches ; while in the notch it distributes palpebral filaments to the 

 upper eyelid. 



The muscular branches referred to are comparatively small, and supply the corrugator 

 of the eyebrow, the occipito-frontalis, and the orbicular muscle of the eyelids, joining 

 the facial nerve in the last muscle. The cutaneous branches, among which two (outer 

 and inner) may be noticed as the principal, are placed at first beneath the occipito- 

 frontalis. The outer one, the larger, perforates the tendinous expansion of the muscle, 

 and ramifies in the scalp as far back as the lambdoidal suture. The inner branch 

 reaches the surface sooner than the preceding nerve, and ends in the integument over 

 the parietal bone. The pericranial branches arise from the cutaneous nerve beneath 

 the muscle, and end in the pericranium covering the frontal and parietal bones. 



Fig. 405. Fig. 405. NERVES OP THE OR- 



BIT FKOM THE OUTER SlDE 



t "&- "$?ifrli (from Sappey after Hirschfeld 



and Leveilld). f 



The external rectus muscle has 

 been divided and turned down: 1, 

 the optic nerve; 2, thetrunkof the 

 third nerve; 3, its upper divisioa 

 pasing into the levator palpebrae 

 and superior rectus ; 4, its long 

 lower branch to the inferior oblique 

 muscle ; 5, the sixth or abducent 

 nerve joined by twigs from the 

 sympathetic ; 6, the Gasserian 



8 7 10 " -A ganglion ; 7, ophthalmic nerve ; 8, 



its nasal branch ; 9, the ophthal- 

 mic ganglion ; 10, its short or 



motor root ; 11, long sensory root from the nasal nerve; 12, sympathetic twig from 

 the carotid plexus ; 13, ciliary nerves passing into the eyeball ; 14, frontal branch of the 

 ophthalmic nerve. 



NASAL BRANCH. 



The nasal branch (oculo-nasalis), separating from its parent trunk in the 

 wall of the cavernous sinus, enters the orbit between the heads of the outer 

 rectus. It then inclines inwards over the optic nerve, beneath the elevator 

 of the upper eyelid and the superior rectus muscle, to the inner wall of the 

 orbit, through which it passes by the anterior internal orbital foramen. In 

 this oblique course across the orbit it furnishes a single filament to the 

 ophthalmic ganglion, two or three (long ciliary) directly to the eyeball ; and, 

 at the inner side of the cavity, a considerable branch (infratrochlear), which 

 issues from the orbit at the fore part. 



On leaving the orbit the nasal nerve is directed transversely inwards to 

 the upper surface of the cribriform plate of the ethmoid bone, and, passing 

 forwards in a groove at its outer edge, within the cranium, descends by a 

 special aperture close to the crista galli at the fore part of the plate to the 

 roof of the nasal fossa, where it divides into two branches, one of which 

 (external or superficial nasal) reaches the integument of the side of the nose, 

 and the other (rainus septi) ramifies in the pituitary membrane. 



