Question

The brachial plexus can be palpated at the lower lateral border of the sternocleidomastoid muscle. Injury to the brachial plexus could cause weakness or paralysis to all of the following EXCEPT the ______.
A. deltoid muscleB. biceps brachii muscleC. sternocleidomastoid muscleD. muscles that flex the wrist and fingers

Answer 1

Answer: C. sternocleidomastoid muscle

Explanation:

The sternocleidomastoid muscle is the most superficial cervical muscle. The primary function of the muscle is the rotation of the head and flexion of the neck.  

The brachial plexus does not cause any harm to the sternocleidomastoid muscle because it is innervated by the cranial nerve (accessory) and branches of the spinal nerves C2 and C3 (cervical).