Denticulate ligaments


The denticulate ligaments are triangular shaped ligaments that anchor the spinal cord along its length, at each side, to the dura mater. The bases of the ligaments arise in the pia mater and they are firmly attached to the arachnoid mater and dura mater at the apex. They have 21 attachments per side. Named for their tooth-like appearance, the denticulate ligaments are traditionally believed to provide stability for the spinal cord against motion within the vertebral column.
From a clinical standpoint, denticulate ligaments do not play a significant role in lumbar spinal stenosis when compared to issues such as disc herniations, facet hypertrophy, shape of spinal canal, size of spinal canal, ligamentum flavum hypertrophy, or degenerative joint disease resulting in bony osteophyte formation.

Structure

Each denticulate ligament is composed of a single narrow fibrous strip that extends from the craniovertebral junction to T12. Each ligament features 18-20 triangular extensions that attach to the dura at their apices. The triangular extensions are smaller and more numerous at the cervical levels, and are larger and less numerous at the thoracic levels. The apices of the extensions attach to the dura via fibrous bands at cervical levels and lower thoracic levels, whereas they attach directly to the dura at upper thoracic levels.
The narrow fibrous strip of the denticulate ligament features longitudinally oriented collagen fibers, whereas the triangular extensions are composed of transverse and obliquely oriented collagen fibers. The collagen fibers are thicker and more abundant at the cervical than at the thoracic levels.
These ligaments may be affected by altered motion and position of the vertebral segments.

Mechanical properties

Denticulate ligaments are characterised by high extensibility and relatively low force necessary to rupture them. Their strength, especially in cervical region, decreases in caudal orientation.

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