OPHTHALMIC DIVISIOX OF THE FIFTH NERVE 



51 



foramen rotunduin. The tliinl (livisioii jiasscs through tlie foramen ovale in front 

 of the motor root of the fifth nerve, with which it unites, as already described, 

 to form the mandibular (inferior maxillary) division. The Gasserian ganglion 

 receives communications from the carotid i)lexus of the sympathetic, and is said to 

 furnish some minute twigs to the dura mater. 



First or Ophthalmic Division of the Fifth Nerve 



The ophthalmic is the smallest of the three divisions of the fifth, and is entirely 

 sensory in function. It passes forwards and inwards in the outer wall of the 

 cavernous sinus, where it is placed below and external to the fourth nerve. Behind 

 the sphenoidal fissure it divides into three branches. These branches pass through 

 the sphenoidal fissure, piercing the fibrous derivative of the dura mater Avhich closes 

 it. Two of them, the frontal and the lachrymal, enter the orbit above the external 

 rectus muscle. The remaining branch, the nasal, passes between the two heads of 

 that muscle. In its course in the outer Avail of the cavernous sinus the o])hthalnjic 

 division receives communications from the carotid plexus of the sympathetic, and 

 gives off a tentorial )>ranch (nervus recurrens rami primi, Luschka) which runs l)ack- 

 wards for a short distance within the sheath of the fourth nerve, and is distributed 



Fig. 445. — Nerves of the Orbit, from the Outer Sihe. 

 (From f?appey, after Hirschfeld aud Leveille.) 



LEyriCVLAR G.iyGLION 

 SUPERIOR DIVISION OF THE THIRD NERVE 



SUPRAORBITAL 

 NERVE 



SHORT CILIARY 

 NERVES 



BRANCH OF THIRO TO 

 INFERIOR OBLIQUE 



NASAL BRANCH OF OPHTHA LMIO 



LONG ROOT OF LENTICU- 

 LAR GANGLION 



OPTIC NER VE 



THIRD NERVE 

 SIXTH NERVE 

 GASSERIAN GANGLION 



OPllTHA LMIf I) 1 1 ISION 

 OF FIFTH NERVE 



SHORT ROOT OF SYMPA THETK' ROOT OF LENTICULAR 



LENTICULAR GANGLION GANGLION 



between the layers of the tentorium cerebelli. It also gives communicating 

 branches to the third, fourth, and sixth nerves. The orbital muscles receive their 

 sensory supply through these communications. 



(1) The frontal nerve is the largest brancli of tlic ophthalmic division. It 

 passes forwards and ui)wards on the inner side of tlic third nerve, and enters tlie 

 orbit immediately external to, and a little below, the fourth nerve. It passes for- 

 wards between the periosteum of the orbit and tlie levator ])alpebiw superioris 

 muscle, and, a little behind the middle of the orbit, divides into two branches, 

 termed the supraorbital and supratrochlear. 



(2) The supraorbital nerve leaves the or})it by passing through the sui)raor])ital 

 notch or foramen, where it gives twigs to the upper eyelid, and turns upAvards on 

 the frontal bone, accompanied by the supraorbital artery. It dlA'ides into tAvo 

 branches, an external and an internal. Both these ])ranches divide into several 

 twigs, AA'hich pass A'ery obli(]uely through the anterior l)elly of the occipito-frontalis 

 muscle, and sui)))ly the integument of the forehead and fore ])art of the scalp. The 

 external branch, Avhich is considerahly larger tlian the internal, may be traced 

 backwards nearly as far as the lamlxloidal suture. 



(3) The supratrochlear nerve is directed forwards an<l inwards above the 

 pulley of the superior ot)li(jue nuiscle. It connnunieates Avith the infratrochlear 



