Brachial Plexus

Question

1. Which of the following is NOT part of the brachial plexus?

1. A) Median nerve
2. B) Musculocutaneous nerve
3. C) Vagus nerve
4. D) Ulnar nerve

Answer 1

Answer: (C) Vagus Nerve

Rationale for Correct Answer (C)

Vagus nerve (CN X) is one of the 12 cranial nerves. The 12 cranial nerves can be recalled by the following mneumonic: "Oh Oh To Touch And Feel A Velvet Green Vest, Ah"

The 12 cranial nerves, in order, are: Olfactory (I), responsible for smell; Optic (II), for vision; Oculomotor (III), for eye movement and pupil constriction; Trochlear (IV), for eye movement via the superior oblique muscle; Trigeminal (V), for facial sensation and chewing; Abducens (VI), for eye movement via the lateral rectus muscle; Facial (VII), for facial expressions and taste from the anterior two-thirds of the tongue; Vestibulocochlear (VIII), for hearing and balance; Glossopharyngeal (IX), for taste from the posterior one-third of the tongue and swallowing; Vagus (X), for parasympathetic control and speech; Accessory (XI), for shoulder and neck movement; and Hypoglossal (XII), for tongue movement.

Rationales for Incorrect Answers (A, B, D):

Terminal Branches for Brachial Plexus can be recalled using the mneumonic "MARMU":

M: Musculocutaneous n (C5-7)

A: Axillary n. (C5-6)

R: Radial n. (C5-T1)

M: Median n. (C5-T1)

U: Ulnar n. (C8-T1)

Answer 2

Answer: C) Vagus nerve

Explanation: The brachial plexus is a network of nerves that originates from the spinal segments C5 to T1 and gives rise to nerves like the median, musculocutaneous, and ulnar nerves. The vagus nerve, however, is not part of the brachial plexus; it arises from the cervical part of the parasympathetic nervous system.