Comparison of three-dimensional facial morphology between upright and supine positions employing three-dimensional scanner from live subjects

Abstract

Facial soft tissue thicknesses (FSTT) measurements collected from Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) imaging techniques are most commonly taken in the supine position for forensic craniofacial reconstruction. FSTT have been shown to be different in comparison to the upright position due to gravity. The variation of facial morphology between the upright and supine position of laser-scanned images taken from 44 individuals was investigated using volumetric analysis with deviation maps. Between 82.4% and 86.7% of the facial surface area were within the error range of ±2mm between the supine and the upright position. This indicates that most anatomical landmarks taken from the MRI and CT data can be an accurate representative of the FSTT in the upright position. Seven landmarks located around the buccal region, masseteric region and the nasolabial region of the face showed the greatest FSTT deviation between the upright and supine position, thus these landmarks may affect the accuracy of facial reconstructions when using a CT or MRI database.

Patient Satisfaction with Absorbable Anchoring Facial Threads

“…The variation with position can be explained by many factors, among which are the gravity effect and the role of the suspensory ligaments. 23 Lifting areas highly affected by gravity need a higher tension and lifting power. This is better provided by anchoring the thread to a rigid structure like muscular fascia or bone periosteum.…”

Craniofacial anthropometric investigation of relationships between the nose and nasal aperture using 3D computed tomography of Korean subjects

“…Gravity can affect the ala nasi and nasal region if the subject undergoes CT in supine position, causing deformation of the nasal soft tissues. Bulut et al investigated how the facial soft tissue thickness is influenced by the position of the head (i.e., upright versus supine) 25 . They used 3D laser scanned facial images to compare two positions, which revealed that the largest soft tissue deviations occurred in the mouth, cheeks, and masseter region because of downward sagging of the flesh caused by gravity.…”

Craniofacial Reconstruction in Mummy Studies

“…Furthermore, numerous average FSTT datasets have been compiled based on living subjects using a wide range of medical imaging equipment (Drgáčová et al 2016;Parks et al 2017;Sandamini et al 2018;Ayoub et al 2019). Studies on facial soft tissue changes according to body position have also been conducted, yielding information that will be invaluable for the application of FSTT data to CFR (Baillie et al 2016;Bulut et al 2017).…”