Perdurography is considered to be the best way for the measurement of the thickening of the ligamentum flavum in the cervical region. 119 cases of peridurography were observed for this purpose. The more the disc space is narrow and or posterior spur is large in plain X-ray of cervical spine, the thicker the ligamentum flavum is in peridurography. At the extension position of cervical spine, the inward bulgings of ligamentum flavum are strikingly observed, at the neutral position they are mild but they are significantly reduced at the flexion position.
