Correction method for determining anteroposterior diameter of the cervical spinal canal on lateral radiographs.

SUMMARY: Measurement of the anteroposterior diameter of the cervical spinal canal may prove unreliable because of the rotatory effect of degenerative disease. Nevertheless, this measuring error may be corrected by performing dual midpoint measurements between the posterior vertebral body and spinolaminar line when less than 10 degrees of rotation is present.