Noninvasive measurement of cervical tri-planar motion in normal subjects.

An electronic digital inclinometer was used to obtain normative data on cervical mobility from 58 normal subjects. They consisted of 28 males (age range, 17-61) and 30 females (age range, 19-62). The measurements were taken from occiput to T1 in flexion-extension, lateral bend, and axial rotation, isolating the regional motion by measuring simultaneously the upper and lower margins of the eight mobile segments. A comparison of radiographs and inclinometer measures showed excellent correlations (r < 0.9997, P < 0.05). Normative data are presented. Gender-specific regional mobility differences occurred only in cervical extension, whereas no consistent age-related differences were found. Stiffer individuals could be found in either gender or any age group, but rigidity in one plane did not necessarily predict rigidity in another.