A maxillary anterior periapical radiograph shows a thin vertical RADIOLUCENT line running in the midline between the central incisors, extending superiorly. What is this structure?

Correct answer: D. The median palatine (intermaxillary) suture

• A. A vertical root fracture is confined WITHIN a root, does not run in the midline between two teeth, and is accompanied by clinical findings — a deep isolated probing defect, pain on biting and a J-shaped or halo radiolucency.
• B. The nasolabial fold can cast a soft-tissue shadow on maxillary radiographs, but it appears as a broad diagonal band of altered density, not a fine midline vertical line.
• C. The NASOPALATINE (incisive) canal and its foramen produce a ROUND, OVAL or heart-shaped radiolucency between and above the central incisor apices — not a thin linear one. A radiolucency exceeding roughly 6 mm there raises the possibility of a nasopalatine duct cyst.
• D. CORRECT. The MEDIAN PALATINE SUTURE — also called the intermaxillary suture — is the fibrous joint between the two maxillae. On a maxillary anterior periapical it appears as a THIN, straight, vertical radiolucent line in the midline between the central incisors, extending superiorly and often bounded by two thin radiopaque borders of cortical bone. It is entirely normal anatomy and requires no intervention.

Note: Normal midline maxillary landmarks worth being able to name on sight: median palatine suture (thin vertical radiolucent line), incisive foramen (oval/heart-shaped radiolucency), anterior nasal spine (V-shaped radiopacity), nasal septum (broad vertical radiopacity) and the floor of the nasal fossa.