Denticulate ligaments

{{Short description|Ligaments of the spine}}

{{Use dmy dates|date=April 2017}}

{{Infobox anatomy

| Name = Denticulate ligaments

| Latin = ligamentum denticulatum

| Image = Gray767.png

| Caption = The medulla spinalis and its membranes. (Ligamentum denticulatum labeled vertically at bottom left.)

| Image2 = Gray770-en.svg

| Caption2 = Diagrammatic transverse section of the medulla spinalis and its membranes. (Denticulate ligament not labeled, but region is visible.)

| System =

}}

Denticulate ligaments are lateral projections of the spinal pia mater{{Cite book |last=Sinnatamby |first=Chummy |title=Last's Anatomy |publisher= |year=2011 |isbn=978-0-7295-3752-0 |edition=12th |pages=453}} forming triangular-shaped ligaments that anchor the spinal cord along its length to the dura mater on each side.{{cite book |last1=Carpenter |first1=Malcolm |title=Core text of neuroanatomy |date=1984 |publisher=Williams & Wilkins |isbn=978-0683014556 |page=2 |edition=3rd}} 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 roots of T12 and L1. The denticulate ligaments are traditionally believed to provide stability for the spinal cord against motion within the vertebral column.{{Citation needed|date=January 2023}}

Their tooth-like appearance originates the word which derives from Latin denticulatus, from denticulus (meaning ‘small tooth’).Denticulate. (n.d.) The American Heritage® Medical Dictionary. (2007). Retrieved March 8, 2021 from [https://medical-dictionary.thefreedictionary.com/denticulate]

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 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{{Citation needed|date=January 2023}} in between successive nerve roots. 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 {{Convert|3|–|5|mm|abbr=on}} long) and lower thoracic levels ({{Convert|21|–|26|mm|abbr=on}} long), whereas they attach directly to the dura at upper thoracic levels.{{Citation needed|date=January 2023}}

These ligaments may be affected by altered motion and position of the vertebral segments.{{Citation needed|date=January 2023}}

= 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.{{Citation needed|date=January 2023}}

= 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.{{cite journal|last=Polak|title=Biomechanical characteristics of the porcine denticulate ligament in different vertebral levels of the cervical spine—Preliminary results of an experimental study|doi=10.1016/j.jmbbm.2014.02.010|pmid=24583921|volume=34|journal=J Mech Behav Biomed Mater|pages=165–70|year=2014}}

Clinical significance

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.{{Citation needed|date=January 2023}}

Additional images

{{wide image|Gray796.png|400px|A portion of the spinal cord, showing its right lateral surface. The dura is opened and arranged to show the nerve roots.}}

Sources

{{No footnotes|article|date=May 2014}}

  • {{cite journal |vauthors=Polak K, Czyż M, Ścigała K, Jarmundowicz W, Będziński R |title=Biomechanical characteristics of the porcine denticulate ligament in different vertebral levels of the cervical spine — Preliminary results of an experimental study |journal=Journal of the Mechanical Behavior of Biomedical Materials |volume=34 |pages=165–170 |date=June 2014 |pmid=24583921 |doi=10.1016/j.jmbbm.2014.02.010}}
  • Clinically Oriented Anatomy. Moore, Keith and Arthur F. Dalley. Philadelphia, Lippincott Williams & Wilkins 2006.
  • {{cite journal |vauthors=Tubbs RS, Salter G, Grabb PA, Oakes WJ |title=The denticulate ligament: anatomy and functional significance |journal=Journal of Neurosurgery |volume=94 |issue=2 Suppl |pages=271–5 |date=April 2001 |pmid=11302630 |doi=10.3171/spi.2001.94.2.0271}}
  • {{cite book | author = RC Schafer DC | title = Basic Principles of Chiropractic Neuroscience - Chapter 5; Neuroconceptual Models of Chiropractic ACA Press 1998}}
  • {{cite journal |vauthors=Ceylan D, Tatarlı N, Abdullaev T |title=The denticulate ligament: anatomical properties, functional and clinical significance |journal=Acta Neurochirurgica |volume=154 |issue=7 |pages=1229–34 |date=July 2012 |pmid=22555553 |doi=10.1007/s00701-012-1361-x|s2cid=24391896 |display-authors=etal}}

See also

{{Anatomy-terms}}

References

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