. Text-book of nervous diseases; being a compendium for the use of students and practitioners of medicine . ies. The Ocular Muscles. Anatomy.—It will help the student in learning the diseases ofthe cranial nerves if their points of origin and general relation areshown, as in the accompanying illustration (Fig. 53). The motor nerves of the eye are: (a) The third or oculo-motorius, supplying the internal, superior,and inferior recti, inferior obliquus, the levator palpebrae, the ciliarymuscle, and constrictor of the iris. (b) The fourth or trochlears, suppyling the superior oblique. (c) The sixt
. Text-book of nervous diseases; being a compendium for the use of students and practitioners of medicine . ies. The Ocular Muscles. Anatomy.—It will help the student in learning the diseases ofthe cranial nerves if their points of origin and general relation areshown, as in the accompanying illustration (Fig. 53). The motor nerves of the eye are: (a) The third or oculo-motorius, supplying the internal, superior,and inferior recti, inferior obliquus, the levator palpebrae, the ciliarymuscle, and constrictor of the iris. (b) The fourth or trochlears, suppyling the superior oblique. (c) The sixth or abducens, supplying the external rectus. (d) The sympathetic, consisting of fibres from the upper cervical MOTOR DISORDERS OF SPECIAL NERVES. 99 nerves to the dilators of the iris, to its blood-vessels, and to Midlersmuscle. Motor fibres from the nucleus belonging to the third nerverun out with the fibres of the seventh (Mendel), supplying the orbic-ularis palpebrarum. The third and fourth nerves arise from a series of nuclei in thedoor of the aqueduct of Sylvius. They leave the brain at the an-. Fig. 53.—Showing the Apparent Origin of thu Cranial Nerves. terior edge of the pons. They run in the cavernous sinus and enterthe orbit through the sphenoidal fissure. The sixth nerve arises from a nucleus in the floor of the fourthventricle. It emerges at the posterior edge of the pons, runs in thecavernous sinus, and enters the orbit through the anterior laceratedforamen. The nuclear gray matter from which these nerves arise is made 100 DISEASES OF THE NERVOUS SYSTEM. up of a series of nests of cells and each pair supplies a different setof muscles of the eye, as shown in the diagrams (Figs. 56 and 57). The nucleus of the sixth lies farther back in the floor of themedulla, but it belongs to the same serial deposit of gray matter andrepresents the continuation of the anterior horn of the spinal cord(Fig. 56). The motor nerves of the eye, third, fourth, and sixth, are closelyc
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