What anatomical landmark is defined as the lowest point in the inferior margin of the orbit?

The anatomical landmark defined as the lowest point in the inferior margin of the orbit is the orbitale. This point is significant in cephalometric analysis as it provides a reference for various measurements related to the skull and facial structure. The orbitale is essential in diagnosing and planning orthodontic treatment, as it helps in understanding the relationship between the maxilla and the mandible, as well as the overall vertical dimension of the face.

The other choices refer to different anatomical landmarks; for instance, pronasale is located at the tip of the nose, inferior labial sulcus is a groove located above the lower lip, and subnasale is located at the junction of the nose and upper lip. Each of these landmarks serves distinct purposes in facial analysis, but they do not represent the lowest point of the orbit, which is why they do not pertain to the question.