The mandible, or lower jaw, has numerous muscles attached to its body and ramus (vertical portion attached to its body and ramus (vertical portion). Muscles attach to the mandibular body on both its external and internal surfaces, while the ramus primarily supports the muscles of mastication (chewing). Muscles attached to the mandibular body: External (lateral) surface: Mentallis Buccinator Platysma Depressor labii inferioris Depressor anguli oris