Final answer:
In a lateral excursion of the mandible to the right, the ML cusp of the maxillary right first molar passes through the buccal groove of the mandibular right first molar.
Step-by-step explanation:
When the mandible moves to the right in a lateral excursion, the mesiolingual (ML) cusp of the maxillary right first molar passes through the buccal groove of the mandibular right first molar. This movement is part of the dynamic occlusion that occurs when the jaws move side to side, which is facilitated by the condylar and coronoid processes of the mandible, the only moveable bone of the skull.
During this lateral movement, the teeth slide against each other while the mandibular foramen remains stationary, demonstrating the complexity of the human masticatory system.
When the mandible moves to the right, the ML cusp of the maxillary right first molar passes through the central groove of the mandibular right first molar. This occurs during lateral excursion, which is the side-to-side movement of the mandible away from the midline.