ALT Method for estimating osteological digital range of motion (oROM). Assembled vertebral columns of a cat (A) and tegu (B), showing the locations of the center of rotations using the zygapophysis (purple) and disk (red) approach. (C) Each motion segment consists of an anterior and posterior vertebra (cat, L5–L6). Landmarks were placed at the centrum extremes (dorsal, ventral, left, right; blue: anterior landmarks; pink: posterior landmarks), as well as the anterior and posterior extremes of the left zygapophysis. Limits on motion are determined by bony intersection between vertebrae, disarticulation of the zygapophyses, and strain at the centra. (D) Coordinate system for vertebral bending, where the x-axis is axial rotation, y-axis lateral bending, and z-axis sagittal bending.