66-year-old woman is unable to open her mouth or jaw because of tetanus resulting from a penetrating wound from a rusty nail. Which of the following muscles would most likely be paralyzed?: (A) A, (B) B, (C) C, (D) D
Answer is B. Lateral pterygoid muscle opens the mouth by depressing the jaw. Masseter, medial pterygoid, and temporalis muscles close the jaw. Buccinator muscle is a muscle of facial expression.