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3d cranial nerve; supplies all the extrinsic muscles of the eye, except the external rectus and superior oblique, and also the levator palpebrge superior is, the ciliary muscle, and the sphincter irid is; its origin is the floor of the a que educt us cerebri, it emerges from the brain in the oculomotor sulcus, pierces the dura mater to the side of the posterior clinoid proce , pa es through the cavernous sinus and enters the orbit through the superior orbital (sphenoidal) fi ure. n. olfacto'rius [BNA], olfactory nerve, ist cranial, nerve of smell; one of 20 nerves on each side, arising from the olfactory bulb and distributed to the nasal mucous membrane. n. ophthal'mic us [BNA], ophthalmic nerve, the ophthalmic branch of the trigeminus, pa es forward from the semilunar ganglion in the outer wall of the cavernous sinus, entering the orbit through the superior orbital (sphenoidal) fi ure; through its branches, frontal, lacrymal, and nasocihary, it supplies sensation to the orbit and its contents, the anterior part of the nasal cavity, and the skin of the forehead. n. op'tic us [BNA], optic nerve, 2d cranial nerve of sight; taking origin from the retina, pa es out of the orbit through the optic foramen to the chiasm, where most of the fibers cro to the opposite side and pa through the optic tract to the geniculate bodies and superior corpora quadrigemina. n. orbita'lis, orbital nerve, n. zygomatic us [BNA]. n. palati'nus [BNA], palatine nerve, one of a number of branches, anterior, middle (external) and posterior,, from the sphenopalatine ganglion, supplying the mucous membrane of the palate. n. pat he ficus, pathetic nerve, fourth nerve, n. trochlear is [BNA]. n. perine'i [BNA], perineal nerve, the superficial terminal branch of the pudendal nerve, supplying most of the muscles of the perineum as well as the skin of that region. n. peronse^us commu'nte [BNA], common peroneal nerve, external popliteal nerve, one of the terminal divisions of the sciatic, pa ing through the later a portion of the popliteal space to opposite the head of the tibia where it divides into the superficial and deep peroneal nerves. n. peroQs'us profun'dus [BNA], deep peroneal nerve, anterior tibial nerve, one of the terminal branches of the common peroneal nerve; pa ing down the front* of the leg on the front of the intero eous membrane and lower part of the tibia, supplying the tibial is anterior, extensor proprius hallucis, extensor long us digitorum, and per on as us tertius muscles, and also the skin of the great toe and inner surface of the 2d toe. n. peronee'us superficia'Iis [BNA], superficial peroneal nerve, musculocutaneous nerve, a branch of the common peroneal, pa es downward in front of the fibula to the lower third of the leg where it divides into branches supplying the long and short peroneal muscles and the skin of the dorsum of the foot and the toes. n. petro's us profuc'dus [BNA], deep petrosal nerve, great deep petrosal branch of the carotid plexus, the sympathetic part of the Vidian nerve; it arises from the internal carotid plexus and joins the larger superficial petrosal at the entrance of the pterygoid canal. n. petro's us superficia'lis ma'^jor [BNA], larger superficial petrosal nerve, the motor part of the Vidian nerve, a branch of the geniculate ganglion of the facial nerve, running through the groove on the anterior surface of the pyramid of the temporal bone to the foramen lacerum and the pterygoid canal. n. petro's us superficia'lis mi'nor [BNA], le er superficial petrosal nerve, the sensory root of the otic ganglion, derived from the tympanic plexus; it leaves the tympanum through the superior tympanic canaliculus and pa es within the cranium to the sphenopetrosal fi ure, through which or the foramen in nomina tum it reaches the otic ganglion. n. pharynge'uSt one of several nerves of the pharynx, branches of the sympathetic, glo opharyngeus, and vagus. n. phren'icus [BNA], phrenic nerve, arises from the cervical plexus, chiefly from the fourth nerve, pa es downward in front of the scalenus anterior and enters the thorax between the subclavian artery and vein behind the sternoclavicular articulation; it then pa es