All of the following are JAW CLOSING muscles EXCEPT:

The lateral pterygoid (inferior head) is a jaw OPENING muscle. During opening, the inferior head of the lateral pterygoid pulls the condyle and disc forward (translation). Jaw CLOSING muscles: masseter, medial pterygoid, temporalis (all fibers elevate the mandible). The lateral pterygoid (superior head) stabilizes the disc during closure, but the inferior head protrudes/opens. This is a fundamental masticatory muscle question.