Anatomy & Physiology Nervous #18

Question

Which cranial motor nerve controls the movement of the trapezius and sternocleidomastoid muscles of the shoulder?

Answers

  1. Abducens
    • Rationale:

      The abducens, or cranial nerve VI, is responsible for the abduction of the eye. It does not play a role in controlling the movement of the sternocleidomastoid and trapezius muscles of the shoulder.

  2. Trigeminal
    • Rationale:

      The trigeminal, or cranial nerve V, is responsible for chewing. It does not play a role in controlling the movement of the sternocleidomastoid and trapezius muscles of the shoulder.

  3. Spinal accessory
    • Rationale:

      The spinal accessory nerve, a motor cranial nerve, is responsible for the movement of the sternocleidomastoid and trapezius muscles of the shoulder.

  4. Glossopharyngeal
    • Rationale:

      The glossopharyngeal, or cranial nerve IX, is responsible for the secretion of saliva from the parotid gland and taste impulses. It does not play a role in controlling the movement of the sternocleidomastoid and trapezius muscles of the shoulder.

Overview

Cranial nerves arise from the brain, not the spinal cord, and pass through separate openings in the skull.

Explanation

Learning Outcomes

There are 12 pairs of cranial nerves. Some function as sensory nerves while others function as motor nerves; there are some cranial nerves that serve both functions. The spinal accessory nerve, or cranial nerve XI, is responsible for controlling the movement of the sternocleidomastoid and trapezius muscles of the shoulder.

Test Taking Tip

Consider the function of each cranial nerve to determine the correct answer choice for this question.

Video Rationale