Which anatomical landmark marks the dorsal surface of the maxilla at the level of the nasal floor?

The anatomical landmark that marks the dorsal surface of the maxilla at the level of the nasal floor is the posterior nasal spine. This bony prominence is located at the posterior aspect of the nasal cavity and plays a critical role in cephalometric analysis. It serves as an important reference point in orthodontic and maxillofacial growth studies, allowing practitioners to assess the relationships and dimensions of various craniofacial structures.

In a cephalometric context, understanding the position of the posterior nasal spine is essential for evaluating the maxilla and its interaction with other facial structures. It helps in determining various skeletal relationships, which are vital for planning treatment options in orthodontics, orthognathic surgery, and facial aesthetics.

The other landmarks listed, such as the subnasale, superior labial sulcus, and labrale inferius, are important in their respective contexts but do not specifically denote the dorsal surface of the maxilla at the level of the nasal floor. The subnasale marks the junction between the nasal and upper lip regions; the superior labial sulcus indicates the groove above the upper lip; and the labrale inferius refers to the inferior border of the lower lip. None of these adequately represent the dorsal aspect of the maxilla