title: Analysis of motion of the head.
abstract: This study was undertaken to determine the geometric form of the surface on which a fixed point on the head moves as a result of neck motion. Motion of a retroreflective marker on the glabella of six normal subjects was stereoscopically recorded by two video cameras, during a variety of neck motions, performed on command. Near real-time computer analysis in three dimensions of the video images showed the marker moved on a surface that very closely approximated an elliptical paraboloid (with tendency to a hemisphere), after extraneous shoulder motion had been eliminated. Parameters defining the elliptical paraboloids were obtained. Using a reflex microscope, the shape of the articular facets on skull base and superior facets of C1 and C2 of 6 normal subjects were examined. The shapes of all these facets were calculated and also found to be elliptical paraboloids.
authors.affiliation: Department of Biomedical Engineering, University of Cape Town, South Africa.
authors.forename: L P
authors.initials: LP
authors.lastname: Adams
authors.forename: A
authors.initials: A
authors.lastname: Tregidga
authors.forename: J P
authors.initials: JP
authors.lastname: Driver-Jowitt
authors.forename: P
authors.initials: P
authors.lastname: Selby
authors.forename: S
authors.initials: S
authors.lastname: Wynchank
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000502:physiology*; D005260:Female; D006257:Head / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D014743:Videotape Recording