Dura mater
Dura mater | |
---|---|
tentorium cerebelli etc. | |
Details | |
Pronunciation | UK: /ˈdjʊərə ˈmeɪtər/, US: /- ˈmætər/ |
Precursor | Neural crest |
Part of | Meninges surrounding the brain and spinal cord |
Identifiers | |
Latin | dura mater |
MeSH | D004388 |
TA98 | A14.1.01.101 A14.1.01.002 |
TA2 | 5370 |
FMA | 9592 |
Anatomical terminology] |
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. The other two meningeal layers are the arachnoid mater and the pia mater. It envelops the arachnoid mater, which is responsible for keeping in the cerebrospinal fluid. It is derived primarily from the neural crest cell population, with postnatal contributions of the paraxial mesoderm.[1]
Structure
The dura mater has several functions and layers. The dura mater is a membrane that envelops the arachnoid mater. It surrounds and supports the dural venous sinuses that reabsorbs cerebrospinal fluid and carries the cerebral venous return back toward the heart.
Cranial dura mater has two layers or
Folds and reflections
The dura separates into two layers at dural reflections (also known as dural folds), places where the inner dural layer is reflected as sheet-like protrusions into the cranial cavity. There are two main dural reflections:
Two other dural infoldings are the cerebellar falx and the sellar diaphragm:
- The cerebellar falx (falx cerebelli) is a vertical dural infolding that lies inferior to the cerebellar tentorium in the posterior part of the posterior cranial fossa. It partially separates the cerebellar hemispheres.
- The sellar diaphragmis the smallest dural infolding and is a circular sheet of dura that is suspended between the clinoid processes, forming a partial roof over the hypophysial fossa. The sellar diaphgram covers the pituitary gland in this fossa and has an aperture for passage of the infundibulum (pituitary stalk) and hypophysial veins.
Blood supply
This depends upon the area of the cranial cavity: in the anterior cranial fossa the anterior meningeal artery (branch from the ethmoidal artery) is responsible for blood supply, in the middle cranial fossa the middle meningeal artery and some accessory arteries are responsible for blood supply, the middle meningeal artery is a direct branch from the maxillary artery and enter the cranial cavity through the foramen spinosum and then divides into anterior (which runs usually in vertical direction across the pterion) and posterior (which runs posteriosuperiorly) branches, while the accessory meningeal arteries (which are branches from the maxillary artery) enter the skull through foramen ovale and supply area between the two foramina, and the in posterior cranial fossa the dura mater has numerous blood supply from different possible arteries:
A. posterior meningeal artery (from the ascending pharyngeal artery through the jugular foramen)
B. meningeal arteries (from the ascending pharyngeal artery through hypoglossal canal)
C. meningeal arteries (from occipital artery through jugular or mastoid foramen)
D. meningeal arteries (from vertebral artery through foramen magnum)
Drainage
The two layers of dura mater run together throughout most of the skull. Where they separate, the gap between them is called a
Arachnoid villi, which are outgrowths of the arachnoid mater (the middle meningeal layer), extend into the dural venous sinuses to drain CSF. These villi act as one-way valves. Meningeal veins, which course through the dura mater, and
Nerve supply
The supratentorial dura mater membrane is supplied by small meningeal branches of the trigeminal nerve (V1, V2 and V3).[5] The innervation for the infratentorial dura mater are via upper cervical nerves and the meningeal branch of the vagus nerve.[6]
Clinical significance
Many medical conditions involve the dura mater. A
In 2011, researchers discovered a connective tissue bridge from the
The dura-muscular, dura-ligamentous connections in the upper cervical spine and occipital areas may provide anatomic and physiologic answers to the cause of the cervicogenic headache. This proposal would further explain manipulation's efficacy in the treatment of cervicogenic headache.[9]
The American Red Cross and some other agencies accepting blood donations consider dura mater transplants, along with receipt of pituitary-derived growth hormone, a risk factor due to concerns about Creutzfeldt–Jakob disease.[10]
Cerebellar tonsillar ectopia, or Chiari malformation, is a condition that was previously thought to be congenital but can be induced by trauma, particularly whiplash trauma.[11] Dural strain may be pulling the cerebellum inferiorly, or skull distortions may be pushing the brain inferiorly.
Dural ectasia is the enlargement of the dura and is common in connective tissue disorders, such as Marfan syndrome and Ehlers–Danlos syndrome. These conditions are sometimes found in conjunction with Arnold–Chiari malformation.
Etymology
The name dura mater derives from the Latin for tough mother (or hard mother),[12] a loan translation of Arabic أم الدماغ الصفيقة (umm al-dimāgh al-ṣafīqah), literally 'thick mother of the brain', matrix of the brain,[13][14] and is also referred to by the term "pachymeninx" (plural "pachymeninges").[13]
Additional images
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Dura mater (spinal section)
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Diagrammatic representation of a section across the top of the skull, showing the membranes of the brain, etc.
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Diagrammatic transverse section of themedulla spinalisand its membranes
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Spinal cord. Spinal membranes and nerve roots. Deep dissection. Posterior view.
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Spinal cord. Spinal membranes and nerve roots. Deep dissection. Posterior view
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Autopsy. Dura mater is retracted by the forceps.
See also
References
- PMID 18228258.
- ^ University of New England, The Dura Mater.
- ^ Shepherd S. 2004. "Head Trauma." Emedicine.com.
- ^ Vinas FC and Pilitsis J. 2004. "Penetrating Head Trauma." Emedicine.com.
- ^ 'Gray's Anatomy for Students' 2005, Drake, Vogl and Mitchell, Elsevier
- S2CID 4763767.
- S2CID 31560001.
- S2CID 26183189.
- ^ Gary D. Hack; Peter Ratiu; John P. Kerr; Gwendolyn F. Dunn; Mi Young Toh. "Visualization of the Muscle-Dural Bridge in the Visible Human Female Data Set". The Visible Human Project, National Library of Medicine.
- ^ International Red Cross and Red Crescent Movement - redcross.org Archived 2005-12-14 at the Wayback Machine
- S2CID 9553904.
- S2CID 242191187
- ^ a b William C. Shiel Jr. "Medical Definition of Dura". Medicine Net. Archived from the original on 2013-12-30. Retrieved 2009-06-01.
- ^ "dura mater (n.)". Etymonline. Douglas Harper.
External links
- Media related to Dura mater at Wikimedia Commons
- youtube: exposure of falx cerebri, dura mater & arachnoid