# Which of the following is a derived cephalometric landmark?
A. Nasion
B. ANS
C. Gnathion
D. Orbitale
The correct answer is C. Gnathion
Anatomic landmarks: These landmarks represent actual anatomic structures of the skull. E.g. Nasion, ANS, PNS, orbitale, pogonion, etc.
Derived landmarks: These are landmarks that have been srbitrarily obtained secondarily from anatomic structures in a cephalogram. E.g. Sella, gnathion, articulare, point PTM, machine porion, etc. They are not anatomical points.
Gnathion: Gnathion is a coonstructed point at the junction of most anterior (Pogonion) and most inferior part (menton) of the chin.
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