Borden method.A straight line is drawn from the superior posterior aspect of the odontoid process of the C2 vertebra to the posterior inferior aspect of the body of the C7 vertebra named line A. Another line is traced along the posterior aspect of the intervening cervical vertebral bodies named line B. The third line intersects A perpendicularly at the point of greatest distance between lines A and B. The length of C recorded in millimeters is the depth of the cervical lordosis.