How Wide Is The Central Canal? Exploring Spinal Anatomy

What is the typical size of the central spinal canal? The normal diameter of the lumbar spinal canal can range anywhere from 15 to 27 millimeters. However, when the spinal canal’s diameter falls below 12 millimeters, it can lead to a condition known as lumbar stenosis. In fact, a diameter as small as 10 millimeters is considered definitively stenotic in some cases (as of February 2, 2022). Lumbar stenosis is a condition where the narrowing of the spinal canal can cause various neurological symptoms and discomfort. Understanding the normal and stenotic dimensions of the spinal canal is crucial in diagnosing and managing this condition effectively.

The central canal’s diameter in MRI varies depending on the age of the individual. In normal subjects, including older children and adults, the central spinal canal typically measures between 1 and 2 millimeters. This measurement is most noticeable in MRI scans, particularly when using heavily T2-weighted sequences with high spatial resolution, such as constructive interference in steady state (CISS) sequences. These sequences enhance the visibility of the central canal, allowing for a more detailed examination of the spinal cord’s structure.