Fig. 3From: The role of iatrogenic foraminal stenosis from lordotic correction in the development of C5 palsy after posterior laminectomy and fusionIshihara Index: defined by the equation \( \mathrm{Index}=\frac{{\displaystyle \sum a1+a2+a3+a4}}{L}\times 100 \) (where a1–4 are the distances between the posterior margins of the inferior endplates of the vertebral bodies and a line between the posterior aspects of the inferior endplates of C2 and C7Back to article page