In the intervertebral spaces, the canal is protected by the ligamentum flavum posteriorly and the posterior longitudinal ligament anteriorly.
It covers the inferior limit of the epidural space and is analogous to the ligamentum flavum found at other levels in the spine.
The structures that are compressing the nerves (usually ligamentum flavum and herniated disc) are then trimmed until the nerves are free from compression.
