Cranial Nerves Iii Iv and VI

These three nerves are grouped together because they all are exclusively involved with eye movements, and routine clinical testing of these movements permits a quick survey of the function of each nerve. The oculomotor nerve (CN III) originates from the oculomotor nucleus in the midbrain and innervates the following muscles: the levator palpebrae, which raises the eyelid; the superior rectus, inferior rectus, medial rectus, and inferior oblique, which mediate most voluntary directions of gaze; and the pupillary sphincter, which constricts the pupil of the eye when light stimulation is provided. The trochlear nerve (CN IV) also begins in the midbrain but innervates only the superior oblique muscle; this muscle moves the eye downward and laterally. The abducens nerve (CN VI) comes from the pons and supplies the lateral rectus muscle, which allows lateral deviation (abduction) of the eye.

Conquering Fear In The 21th Century

Conquering Fear In The 21th Century

The Ultimate Guide To Overcoming Fear And Getting Breakthroughs. Fear is without doubt among the strongest and most influential emotional responses we have, and it may act as both a protective and destructive force depending upon the situation.

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