ANATOMY

Detailed explanation-1: -The oculomotor nerve is the third cranial nerve (CN III). It allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the position of the upper eyelid. Cranial nerve III works with other cranial nerves to control eye movements and support sensory functioning.

Detailed explanation-2: -The oculomotor nerve helps to adjust and coordinate eye position during movement. Several movements assist with this process: saccades, smooth pursuit, fixation, accommodation, vestibulo-ocular reflex, and optokinetic reflex.

Detailed explanation-3: -The oculomotor, trochlear, and abducens nerves are tested by holding a pen or finger 30-40 cm in front of the patient in an H pattern. [1] The patient should follow the target with their eyes, carefully keeping their head still. Any eye deviation, abnormal head posture, or nystagmus should be noted.

Detailed explanation-4: -Background. The oculomotor (third) cranial nerve plays an important role in the efferent visual system by controlling ipsilateral eye movements, pupil constriction, and upper eyelid elevation. Accordingly, damage to the third cranial nerve may cause diplopia, pupil mydriasis, and/or upper eyelid ptosis.

Detailed explanation-5: -Cranial nerves III, IV, VI, XI, and XII are pure motor nerves. Cranial nerves V, VII, IX, and X are mixed sensory and motor nerves. The olfactory nerve (CN I) contains special sensory neurons concerned with smell.