First Cervical Vertebra (Atlas) belongs to the Atlantoaxial joint which connects the base of the skull to the spine. It plays a highly significant role in the growth and function of the craniofacial complex. Atlas has function-anatomical interrelationship with the TMJ. That means the Axis is involved in the morphogenetic and function of the jaws. Aim To investigate the relationship of Atlas's dimensions with jaws rotation in adult orthodontically non-treated subjects using CBCT scan.