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Cranial Nerve 3 - Oculomotor (III)
The oculomotor nerve conveys sensory information from selective muscles of the eye. The motor component controls pupil constriction and movement of some extrinsic eye muscles.
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The motor fibers of cranial nerve III originate in the midbrain and pass through the superior orbital fissure (narrow slit or cleft above the orbit) of the skull (Parent, 1996). These fibers distribute to the upper eyelid and the extrinsic muscles of the eyeball. Parasympathetic control of the ciliary muscle (pupil constriction) of the eyeball and the sphincter muscle of the iris (accommodation) are also supplied by the motor fibers of cranial nerve III. Sensory fibers of this nerve supply proprioception information from muscles of the eyeball. The inability to raise the eyelids following damage to this cranial nerve is called ptosis.
| Reference |
Parent, A. (1996). Carpenter's human neuroanatomy (9th ed.). London: Williams & Wilkins.