Knowledge of the orientation of facet joints in the cervical and upper thoracic region is important for
understanding the biomechanical properties and clinical conditions relevant to the neck. The study was
undertaken on dry macerated bones from 30 adult male human vertebral columns. The orientation of the
superior articular facets in relation to their inclination with the sagittal and transverse planes was examined
between C3 and T3 vertebrae in each column. The linear dimensions of the superior articular facets and the
width/height ratio were also calculated. The results show that all vertebrae at C3 level and 73% at C4 level
displayed posteromedially facing superior articular facets. Similarly at T1 level (C7/T1 joint) and below, all
columns showed posterolaterally facing superior articular facets. The level of change in orientation, from
posteromedial to posterolateral facing superior facets, was not constant and occurred anywhere between C4
(C3/C4 joint) and T1 (C7/T1 joint). The change in orientation followed 2 different patterns, i.e. sudden or
gradual. The C6 vertebra (C5/C6 joint) was the most frequent site to show the transition. The shape of the
superior articular facets was circular to oval at C3, C4 and C5 levels and gradually changed to a
transversely elongated surface at C7 and T1. These findings correlate well with various cervical movements
and associated clinical conditions.