Denticulate ligaments (also known as dentate ligaments) are
lateral
Lateral is a geometric term of location which may refer to:
Healthcare
*Lateral (anatomy), an anatomical direction
* Lateral cricoarytenoid muscle
* Lateral release (surgery), a surgical procedure on the side of a kneecap
Phonetics
*Lateral co ...
projections of the spinal
pia mater
Pia mater ( or ),Entry "pia mater" in forming triangular-shaped
ligament
A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the:
* Peritoneal li ...
s that anchor the spinal cord along its length to the dura mater on each side. There are usually 21 denticulate ligaments on each side, with the uppermost pair occurring just below the foramen magnum, and the lowest pair occurring between
spinal nerve root Spinal nerve root may refer to:
* Posterior root of spinal nerve
* Anterior root of spinal nerve
In anatomy and neurology, the ventral root of spinal nerve, anterior root, or motor root is the efferent motor root of a spinal nerve.
At its dist ...
s of T12 and L1. The denticulate ligaments are traditionally believed to provide stability for the spinal cord against motion within the
vertebral column
The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordata, ...
.
Their tooth-like appearance originates the word which derives from Latin ''denticulatus'', from ''denticulus'' (meaning ‘small tooth’).
Anatomy
The bases of denticulate ligaments arise in the pia mater and are firmly attached to the arachnoid mater and dura mater at the apex. The denticulate ligaments extend across the subarachnoid space between anterior nerve roots and posterior nerve roots, piercing the intervening spinal
arachnoid mater
The arachnoid mater (or simply arachnoid) is one of the three meninges, the protective membranes that cover the brain and spinal cord. It is so named because of its resemblance to a spider web. The arachnoid mater is a derivative of the neural c ...
to reach the dura.
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 in between successive
nerve root A nerve root (Latin: ''radix nervi'') is the initial segment of a nerve leaving the central nervous system. Nerve roots can be classified as:
*cranial nerves, Cranial nerve roots: the initial or proximal segment of one of the twelve pairs of crania ...
s. 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 (each band long) and lower thoracic levels ( long), whereas they attach directly to the dura at upper thoracic levels.
These ligaments may be affected by altered motion and position of the vertebral segments.
Microanatomy/histology
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.
Biomechanics
Denticulate ligaments are characterised by high extensibility (on average 50% of their initial length) and relatively low force necessary to rupture them (around 1 N). Their strength, especially in cervical region, decreases in caudal orientation.
Clinical significance
From a clinical standpoint, denticulate ligaments do not play a significant role in
lumbar spinal stenosis
Lumbar spinal stenosis (LSS) is a medical condition in which the spinal canal narrows and compresses the nerves and blood vessels at the level of the lumbar vertebrae. Spinal stenosis may also affect the cervical or thoracic region, in which case ...
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.
Additional images
Sources
*
*Clinically Oriented Anatomy. Moore, Keith and Arthur F. Dalley. Philadelphia, Lippincott Williams & Wilkins 2006.
*
*
*
See also
*
Filum terminale
The filum terminale ("terminal thread") is a delicate strand of fibrous tissue, about 20 cm in length, proceeding downward from the apex of the conus medullaris. It is one of the modifications of pia mater. It gives longitudinal support to th ...
References
External links
* - "Coverings of the spinal cord."
{{Authority control
LigamentsMeninges