Frankfort Horizontal Plane
Pronunciation: FRANK-fort
Also written as: FHP — Frankfort Horizontal Plane
A craniofacial reference plane passing through the porion and orbitale, used as a standard baseline in cephalometric analysis and clinical photographs.
Full Definition
The Frankfort Horizontal Plane is a standardized craniometric reference plane defined by the line connecting the uppermost point of the external auditory meatus (porion) and the lowest point of the orbital margin (orbitale). In orthodontic practice, it serves as the principal horizontal reference in lateral cephalometric tracings and ensures reproducible patient head positioning for clinical photography and radiographic superimposition. Editors should capitalise all three words as a proper noun. The abbreviated form 'FHP' should be expanded on first use. Do not confuse with the mandibular plane or the Sella-Nasion plane, which are distinct reference lines.
Usage
Usage note: Capitalise as a proper noun. 'Frankfort' is the conventional spelling in dental literature; do not render as 'Frankfurt' without confirming the journal's house style.
In Context
- "All lateral cephalograms were oriented with the Frankfort Horizontal Plane parallel to the floor before landmark digitisation." — Research methods section
- "Ensure 'Frankfort Horizontal Plane' is capitalised consistently and 'FHP' is introduced in parentheses on first use." — Editorial style note