BRAIN
CRANIAL NERVES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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abducens
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facial
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accessory
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hypoglossal
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vagus
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Detailed explanation-1: -The nuclei to the sternocleidomastoid and trapezius muscles appear to be somatotopically arranged in the cervical cord. Motor neurons at C1–2 innervate the sternocleidomastoid, while neurons at C3–4 innervate the trapezius. This innervational pattern can account for isolated weakness of one muscle or the other.
Detailed explanation-2: -The ipsilateral activation of the XI nerve can activate the intrinsic laryngeal muscles fibers for the correct movement of the vocal cords of the same side. The main functions remain those of contracting the trapezius muscle and the sternocleidomastoid.
Detailed explanation-3: -The sternocleidomastoid muscle is innervated by the accessory nerve (cranial nerve XI) and direct branches of the cervical plexus (C2-C3).