This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Facial nerve stimulation during testing of nerve indicated by contraction of which muscle? 
Select and explain. 
A. Temporalis, B. Masseter, C. Sternocleidomastoid, D. Orbicularis oris
D: Orbicularis oris
Answer: D: Orbicularis oris 
Explanation: Facial nerve supplies the muscles of the facial expression like orbicularis oris. 
Muscles of mastication like masseter and temporalis are supplied by the mandibular nerve, a branch of trigeminal nerve.
Spinal accessory nerve supplies sternocleidomastoid and the trapezius.