The Frankfort Plane and Head Positioning in Facial Aesthetic Analysis—The Perpetuation of a Myth

Posición Natural de Cabeza y su relación con el Plano de Frankfurt en cefalometría ortodóncica.

“…En fotogrametría facial, la estandarización de la posición de la cabeza del individuo es fundamental. Existen protocolos que postulan el uso de la Posición Natural de Cabeza (PNC) como estado inicial, mientras que otros postulan al Plano de Frankfurt (PF), paralelo a la Horizontal Verdadera (HV), como la posición inicial idónea (2) . En cefalometría la posición en que se encuentra el paciente al momento de la toma radiográfica está inducida por el aparato radiográfico y el radiólogo busca la paralelización del PF con respecto a la HV, con el propósito de orientar el cráneo de una manera aproximada a la PNC (3) .…”

Positional symmetry of porion and external auditory meatus in facial asymmetry

“…It is defined as the most superior and outer bony surface point of the external auditory meatus and can be called as the anatomical Po [ 1 ]. It has been employed to construct the Frankfort horizontal (FH) plane, which has been frequently used as a horizontal reference plane for the anthropometric and the cephalometric analysis since its introduction in 1884 [ 2 ].…”

Variability of the inclination of anatomic horizontal reference planes of the craniofacial complex in relation to the true horizontal line in orthognathic patients

“…7 It has been suggested that using TrH as an extracranial reference plane may be more reliable than the commonly used intracranial planes, and this is particularly important in orthognathic patients. 8 Therefore, it is crucial that when intracranial planes are used in orthognathic patients, the plane must have an inclination close to the TrH. The importance of the variability of intracranial reference planes is demonstrated in Figure 1.…”

“…7 This is particularly important for orthognathic patients. 7,8 Nevertheless, anatomic reference planes continue to be used, and their reliability should therefore be evaluated.…”

“…The potential individual variability in the inclination of the FH plane in orthognathic surgery patients has been anecdotally noted. 8 However, the hypothesis that the FH, SN-h, and optic planes have significant individual variability in orthognathic patients has not been scientifically evaluated, and there are no previous data on the reliability of anatomic reference planes in relation to the TrH plane in orthognathic surgery patients. The principal objective of this investigation was to compare the inclinations of 3 intracranial reference planes of the craniofacial complex (FH, SN-h, and optic) with the TrH line in presurgical orthognathic patients.…”