Cranio-orbito-zygomatic measurements from standard CT scans in unoperated Treacher Collins syndrome patients: comparison with normal controls.

Fourteen reproducible cranio-orbito-zygomatic measurements taken from 26 standard axial computed tomographic (CT) scans of unoperated individuals with symmetric forms of Treacher Collins syndrome (TCS) were compared to age-matched controls. The interorbital measurements of the TCS patients were at the mean when compared to their cohort group (medial and lateral orbital wall separation), while the zygomatic measurements were significantly less than normal confirming the extent of malar hypoplasia. The congenitally deficient lateral aspect of the orbits in TCS patients was confirmed by the greater than normal values measured for globe protrusion and medial orbital wall protrusion in conjunction with the diminished lateral orbital wall lengths, all of which use the lateral orbital rim as a reference point. The abnormal shape of the anterior cranial vault in patients with TCS was documented as a diminished intercoronal distance (width) and decreased cephalic length when compared to normal age-matched controls.