What condition is characterized by the narrowing of the spinal canal?

Spinal stenosis is a condition that involves the narrowing of the spinal canal, which can lead to pressure on the spinal cord and/or nerve roots. This narrowing can occur due to various factors, including degenerative changes in the spine, herniated discs, thickening of ligaments, or congenital abnormalities. As the space within the spinal canal decreases, it can result in symptoms like pain, numbness, tingling, or weakness, particularly in the limbs.

In contrast, a herniated disc occurs when the inner gel-like core of a spinal disc protrudes through a tear in the outer layer, often leading to localized pain and, in some cases, nerve compression. Kyphosis refers to an abnormal rounding of the upper spine and does not specifically involve the narrowing of the spinal canal. Scoliosis involves a lateral curvature of the spine and also does not directly relate to the narrowing of the spinal canal. Thus, spinal stenosis is distinctly characterized by this specific narrowing, making it the correct response.