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Meninges: Anatomy

The brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and the spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy are enveloped by 3 overlapping layers of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. The meninges function to protect the contents of the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy. Infection of the CNS presents with inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the meninges, and the etiology can be elicited by examining CSF, which is contained within the subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage.

Last updated: Aug 11, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Layers of the Meninges

The meninges are layers of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology that protect the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy.

The meninges consist of 3 layers of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology, with potential spaces between them:

  • Dura mater: outermost layer
  • Arachnoid mater: middle layer
  • Pia mater: innermost layer
Table: Layers of the meninges from superficial to deep
Layer Origin Characteristics
Epidural space Epidural space Space between the dura mater and the walls of the vertebral canal. Epidural Hemorrhage NA
  • Potential space between the dura mater and skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy/ vertebral column Vertebral column The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy
  • Contains blood vessels and fat
  • Site of blood collection in cases of middle meningeal artery Middle Meningeal Artery Epidural Hemorrhage injury
Dura mater Mesoderm Mesoderm The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube. Gastrulation and Neurulation
  • Divided into 2 layers:
    • Superficial periosteal layer
    • Inner meningeal layer
  • Grows adhered to the periosteum Periosteum Thin outer membrane that surrounds a bone. It contains connective tissue, capillaries, nerves, and a number of cell types. Bones: Structure and Types of the calvaria
  • Blood supply: middle meningeal artery Middle Meningeal Artery Epidural Hemorrhage
  • Nerve supply:
    • Trigeminal nerve Trigeminal nerve The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the trigeminal ganglion and project to the trigeminal nucleus of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication. The 12 Cranial Nerves: Overview and Functions branches: innervate supratentorial structures
    • Cervical nerves (C2 and C3): innervate infratentorial structures
Subdural space Subdural space Potential cavity which separates the arachnoid mater from the dura mater. Subdural Hemorrhage NA
  • Potential space between the arachnoid mater and the dura mater
  • Contains “bridging veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology” that run between the cerebral hemispheres and dural venous sinuses Venous sinuses Veins: Histology
  • This space typically exists only under pathologic conditions, such as with a subdural hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception.
Arachnoid mater (leptomeninges) Neural crest Neural crest The two longitudinal ridges along the primitive streak appearing near the end of gastrulation during development of nervous system (neurulation). The ridges are formed by folding of neural plate. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the neural tube. Hirschsprung Disease
Subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage Choroid Choroid The thin, highly vascular membrane covering most of the posterior of the eye between the retina and sclera. Eye: Anatomy plexus
  • Arachnoid/pacchionian granulations: allow CSF to enter from the subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage into the venous system
  • CSF: produced by the choroid Choroid The thin, highly vascular membrane covering most of the posterior of the eye between the retina and sclera. Eye: Anatomy plexus and contained in the subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage
  • The major arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology of the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification run through the subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage.
Pia mater (leptomeninges) Neural crest Neural crest The two longitudinal ridges along the primitive streak appearing near the end of gastrulation during development of nervous system (neurulation). The ridges are formed by folding of neural plate. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the neural tube. Hirschsprung Disease
  • The inner layer of the subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage
  • Adherent to the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification
  • Shiny appearance grossly
  • Highly vascularized
NA: not applicable
Meninges and subarachnoid space

Layers of the meninges and their relationships beneath the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy

Image: “Diagram of section of top of brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification showing the meninges and subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage” by OpenStax. License: CC BY 4.0

Dural Foldings, Reflections, and Sinuses

The dura mater is the thickest layer of the meninges and provides structure to the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification.

Dural foldings and dural sinuses come from the dura mater.

  • Dural foldings separate the right and left hemispheres:
    • Falx cerebri
    • Falx cerebelli
    • Tentorium cerebelli
    • Diaphragma sellae
  • Dural sinuses ( venous sinuses Venous sinuses Veins: Histology) form between layers of dura mater. CSF flows through the dural sinuses.
Table: Characteristics of dural foldings, reflections, and sinuses
Structure Characteristics
Falx cerebri Separates the right and left cerebral hemispheres
Falx cerebelli Separates the right and left cerebellar hemispheres
Tentorium cerebelli Tent, or roof, over the cerebellum Cerebellum The cerebellum, Latin for “little brain,” is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis. Cerebellum: Anatomy
Diaphragma sellae The roof over the pituitary gland Pituitary gland The pituitary gland, also known as the hypophysis, is considered the “master endocrine gland” because it releases hormones that regulate the activity of multiple major endocrine organs in the body. The gland sits on the sella turcica, just below the hypothalamus, which is the primary regulator of the pituitary gland. Pituitary Gland: Anatomy
Dural sinuses The 2 layers of dura mater run together throughout most of the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy. Where they separate, the gap between them is called a dural venous sinus. These sinuses drain blood and CSF from the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and empty into the internal jugular vein Internal jugular vein Parapharyngeal Abscess.
Dural venous sinuses

Dural venous sinuses Venous sinuses Veins: Histology

Image: “Dural venous sinuses Venous sinuses Veins: Histology” by Jmarchn. License: CC BY-SA 3.0, edited by Emma C. Cheshire et al AL Amyloidosis. (2017).

Clinical Relevance

Neoplastic disorders:

  • Meningiomas are the most common cranial neoplasm, arising arise from arachnoidal cells that are found in the arachnoid villi. Meningiomas are typically benign Benign Fibroadenoma, slow-growing tumors, but they can sometimes present in an atypical or malignant fashion. Symptoms of meningiomas depend on their location. The symptoms occur as a result of the tumor Tumor Inflammation compressing nearby structures. The most common treatment is surgical excision. 

Infectious Infectious Febrile Infant disorders:

  • Meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis: inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the meninges that surround the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy. In general, meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis causes symptoms such as headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and stiff neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess. This disease is subdivided into bacterial (most common cause), viral, and parasitic meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis. Infectious etiologies Infectious Etiologies High-Risk Headaches are diagnosed with a lumbar puncture Lumbar Puncture Febrile Infant and must be treated aggressively with antimicrobial medications.

Traumatic disorders:

  • Epidural hemorrhage Epidural Hemorrhage Epidural hemorrhage (EDH) is an event characterized by bleeding into the epidural space between the dural layers of the meninges and the skull. The primary mechanism triggering bleeding is trauma (i.e., closed head injury), which causes arterial injury, most commonly middle meningeal artery injury. Epidural Hemorrhage: bleeding in the space external to the dura mater—right beneath the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy. Epidural hemorrhage Epidural Hemorrhage Epidural hemorrhage (EDH) is an event characterized by bleeding into the epidural space between the dural layers of the meninges and the skull. The primary mechanism triggering bleeding is trauma (i.e., closed head injury), which causes arterial injury, most commonly middle meningeal artery injury. Epidural Hemorrhage most commonly occurs after direct trauma Direct Trauma Toddler’s Fractures to the head. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with loss of consciousness after a direct blow to the head and, occasionally, altered mental status Altered Mental Status Sepsis in Children. If symptomatic, patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship should undergo craniotomy Craniotomy Surgical incision into the cranium. Neurosurgery with evacuation of the hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception.
  • Subdural hemorrhage Subdural Hemorrhage Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage: occurs beneath the dura mater and is usually more chronic than epidural hemorrhages. In infants, subdural hemorrhage Subdural Hemorrhage Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage typically occurs as a result of child abuse Child abuse Child abuse is an act or failure to act that results in harm to a child’s health or development. The abuse encompasses neglect as well as physical, sexual, and emotional harm. Seen in all subsets of society, child abuse is a cause of significant morbidity and mortality in the pediatric population. Child Abuse. In young adults, common causes include bike or car accidents; and in elderly adults, subdural bleeds are usually the result of falls. If symptomatic, patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship should undergo craniotomy Craniotomy Surgical incision into the cranium. Neurosurgery with evacuation of the hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception.
  • Dural sinus thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus: blood clots can form in the dural sinuses as a result of trauma or infection. Dural sinus thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus can lead to hemorrhagic infarction and cerebral edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema. A cavernous sinus thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus is a subtype of dural sinus thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus that occurs because of seeding Seeding The local implantation of tumor cells by contamination of instruments and surgical equipment during and after surgical resection, resulting in local growth of the cells and tumor formation. Grading, Staging, and Metastasis of an infection from the nasal area.

References

  1. Greenberg RW, Lane EL, Cinnamon J, Farmer P, Hyman RA. (1994). The cranial meninges: anatomic considerations. Semin Ultrasound CT MR. https://www.ncbi.nlm.nih.gov/pubmed/7880562
  2. Rai R, Iwanaga J, Shokouhi G, Oskouian RJ, Tubbs RS. (2018). The tentorium cerebelli: a comprehensive review including its anatomy, embryology, and surgical techniques. Cureus. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6168052/
  3. Louveau A, Smirnov I, Keyes TJ, et al. (2015). Structural and functional features of central nervous system lymphatic vessels. https://pubmed.ncbi.nlm.nih.gov/26030524/
  4. Aspelund A, Antila S, Proulx ST, et al. (2015). A dural lymphatic vascular system that drains brain interstitial fluid and macromolecules. J Exp Med. https://rupress.org/jem/article/212/7/991/41853/A-dural-lymphatic-vascular-system-that-drains
  5. Apra C, Peyre M, Kalamarides M. (2018). Current treatment options for meningioma. Expert Rev Neurother. https://pubmed.ncbi.nlm.nih.gov/29338455/
  6. Bi WL, Dunn IF. (2017). Current and emerging principles in surgery for meningioma. Chin Clin Oncol. https://pubmed.ncbi.nlm.nih.gov/28758410/
  7. Hoffman O, Weber RJ. (2009). Pathophysiology and treatment of bacterial meningitis. Ther Adv Neurol Disord. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3002609/
  8. Khairat A, Waseem M. (2020). StatPearls StatPearls. https://pubmed.ncbi.nlm.nih.gov/30085524/
  9. Mehta V, Harward SC, Sankey EW, Nayar G, Codd PJ. (2018). Evidence-based diagnosis and management of chronic subdural hematoma: A review of the literature. J Clin Neurosci. https://pubmed.ncbi.nlm.nih.gov/29428263/
  10. Ziu E, Mesfin FB. (2020). Subarachnoid hemorrhage. StatPearls. https://pubmed.ncbi.nlm.nih.gov/28722987/
  11. Wiemels J, Wrensch M, Claus EB. (2010). Epidemiology and etiology of meningioma. Journal of Neuro-Oncology 99:307–314.
  12. Starr CJ, Cha S. (2017). Meningioma mimics: five key imaging features to differentiate them from meningiomas. Clinical Radiology 72:722–728.
  13. Lee JH. (2008). Meningiomas: diagnosis, treatment, and outcome. Springer Science & Business Media, pp. 3–13.

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