Final answer:
The acanthion is the landmark found at the junction of the nose and the upper lip, essential in medical and dental imaging techniques like cephalometry.
Step-by-step explanation:
The landmark located at the junction of the nose and the upper lip is known as the acanthion. This spot is a significant point of reference in various medical and dental imaging procedures, such as cephalometry, which is used to assess the anatomical relationships within the head. The acanthion is used for precise positioning in order to ensure consistent imaging results.