Which of the following list the three meninges in the correct order from the most superficial layer to the deepest layer?
IntroductionThe meninges (from ‘meninx’ meaning membrane) are a set of distinct membranes that cover and encase the brain and spinal cord. Show
There are three layers from superficial to deep:
You might also be interested in our Anatomy Flashcard Collection which contains over 2000 anatomy flashcards in addition to advanced features such as spaced repetition. 🫁 EtymologyThe term ‘dura mater’ stems from the Latin for ‘hard mother’, in turn being derived from the Arabic for ‘coarse mother’. ‘Hard’ and ‘coarse’ are merely reflections of the dura’s composition. ‘Arachnoid’ refers to the spider-web-like appearance of the arachnoid mater. ‘Pia’ or ‘little’ describes how small and fragile this layer is. Although there are a number of views as to why ‘mater’ is used, it is most often suggested that ‘mother’ refers to the protective nature of the meninges – ‘the mothers of the brain’. Layers of the scalpThe mnemonic SCALP can be used to recall the layers of the scalp:
Function of the meningesThe meninges have two primary functions:
Dura materThe dura mater compartmentalises the brain (via falx cerebri and tentorium cerebelli) thus preventing directional movement of the brain within the cranial vault that would normally cause injury. It also contains the cerebral venous drainage sinuses. Arachnoid materThe arachnoid mater maintains a barrier between the pia and dura mater, creating the subarachnoid space containing the cerebral arteries (that supplies oxygenated blood to the brain parenchyma) and CSF (that provides a cushion for the brain). Pia materThe pia mater has perforations which allow the subarachnoid arterial supply to reach the brain parenchyma. Macroscopic anatomyCompartments of the dura materThe dura mater is comprised of two distinct layers, the periosteal (superficial) and meningeal (deep) layers. Both layers follow the contours of the internal surface of the skull. The meningeal layer invests in and reflects inwards at the cranial sutures creating partitioning ‘walls’ that compartmentalise the brain. The subsequent compartments are:
Clinical relevance: Extradural haematomaAn extradural haematoma is typically caused by an intracranial arterial bleed. Blood accumulates outside the dura, between the periosteal dura and the inner skull surface. The blood is confined by dural investments in cranial sutures. Extradural haematoma appears as a ‘lentiform’ or lens-shaped opacity on a CT scan (resembling half a lemon). The typical presentation of a patient with an extradural haematoma includes:
Clinical relevance: Subdural haematomaA subdural haematoma is typically caused by an intracranial venous bleed, due to rupture of the dural bridging veins. The haemorrhage occurs beneath the dura and above the arachnoid mater. The haemorrhage is not contained by dural investments and therefore can flow freely over the arachnoid surface. A subdural haematoma appears as a crescent-shaped opacity on a CT head scan (somewhat resembling a banana). The typical presentation of a patient with an extradural haematoma includes:
Dura materArterial supplyThe dura mater receives its own blood supply, primarily from the middle meningeal artery (MMA). This artery may be ruptured in blunt trauma to the head, specifically over the pterion, which is the weakest point in the skull and a point at which this artery overlies. The pterion is the meeting point of four cranial bones: the frontal, temporal, parietal and sphenoid bones. This injury results in an extradural (epidural) haematoma as described above. Additionally, the less well described anterior and posterior meningeal arteries that supply the dura within the anterior and posterior cranial fossae, respectively, which are smaller territories than the MMA. Venous drainageBetween the two dural layers are the dural venous sinuses which drain deoxygenated blood from the brain back to the heart via the internal jugular veins (see Figure 8 below or read our guide here). InnervationThe innervation of the dura mater is fairly complex. The dura mater can be divided into two regions, one above and the other below the tentorium cerebelli, forming the supratentorial and the infratentorial regions respectively. The supratentorial dura mater is supplied by the small meningeal branches of the trigeminal nerve (CN V1, V2 and V3). This can be broken down further into:
In contrast, the innervation for the infratentorial dura mater within the posterior cranial fossa is via the upper spinal cord cervical ganglion (includes C1, C2, and C3) as well as the meningeal branch of the vagus nerve (CN X). Figure 7. The course of the middle meningeal artery and its relation to the pterion. 7 Figure 8. The anatomy of the dural venous sinuses. 8Arachnoid materThe arachnoid mater is a transparent, bi-layered structure found directly below the meningeal layer of the dura mater. It consists of loose connective tissue, it is avascular and has no innervation. The subarachnoid space is filled with cerebrospinal fluid (CSF) produced by the choroid plexus that circulates around the brain to:
Clinical relevance: Subarachnoid haemorrhageThe blood vessels that supply the brain parenchyma itself are found within the subarachnoid space. A rupture of these vessels will result in subarachnoid haemorrhage. The typical clinical presentation of a subarachnoid haemorrhage involves:
On CT imaging it presents as an enhancement (an area of hyperdensity or a brighter area – see arrows in Figure 9) tracking around the gyri or sulci, typically around the circle of Willis where ruptures of berry aneurysms can occur. Figure 9. CT image showing a subarachnoid haemorrhage (arrows pointing to the bleed).9 Figure 10. Common sites of intracranial aneurysms 10Pia materThe pia mater is a transparent, single-layered structure found directly superficial to the cortical surface of the brain. It is delicate and firmly adherent to the brain’s surface, and it follows the flow of the sulci and gyri The pia mater is impermeable to water but does allow for blood vessels to pierce through to supply the brain and spinal cord parenchyma Clinical relevance: MeningitisMeningitis is a life-threatening condition in which the pia and arachnoid mater become acutely inflamed. This can be either septic due to a bacterial infection, commonly Neisseria meningitidis, or it can be ‘aseptic’ where the cause can be due to a viral infection, an adverse drug reaction or other systemic diseases. The typical clinical presentation of a patient with meningitis includes:
Spinal cordAt the level of the spinal cord, it is important to note that you will also encounter the same three meningeal layers along the full length. The conus medullaris is the end of the spinal cord proper, which is located at the spinal level L1/2. From the conus medullaris, the pia mater extends caudally, surrounded by a dural sheath. This is the filum terminalis, whose function is to stabilise the spinal cord in the longitudinal plane by attaching to the posterior aspect of the first coccygeal segment. The filum terminalis can be found nestled amongst the cauda equina, which are the individual nerve root fibres that extend inferiorly from the conus medullaris to meet their respective spinal foramina extending out to innervate the lower body. Working laterally from the spinal cord, the meninges extend outwards covering the spinal roots and fusing with the outer membrane of the spinal nerves, the epineurium, as the nerves exit the spinal column via the spinal foramina. Figure 11. The termination of the spinal cord proper, the cauda equina and filum terminalis.11Clinical relevance: Lumbar puncture (LP)A lumbar puncture is an invasive test designed to access the epidural or subarachnoid space in the lower spinal canal. Indications for an LP include CSF analysis (e.g. infection, autoimmune disease) when a sample is obtained from the subarachnoid space as well as to administer drugs such as in epidural analgesia. Relative and absolute contraindications to performing an LP can include raised intracranial pressure (ICP), anticoagulants, clotting disorders, spinal abscesses, acute spinal trauma and congenital spinal deformity. For more information, see the Geeky Medics OSCE guide to performing a lumbar puncture. Figure 12. Illustration of a lumbar puncture being performed with the patient both lying and sitting down.12Key points
ReviewerDr Ian HubbardTeaching Fellow – MBBS Biomedical Science EditorArunachalam SomaReferencesText references
Image references
What are the 3 meningeal layers going from superficial to deep?From superficial to deep the meninges are the: Dura mater, also known as the pachymeninx. Arachnoid mater. Pia mater.
What is the correct order of the meninges from most superficial to deepest?Three layers called the meninges encase the brain and spinal cord. From superficial to deep, these layers are the dura mater, arachnoid mater, and pia mater.
Which of the following list the three meninges in the correct order from the most superficial to the deepest layer?Correct answer:
The tough dura mater is the outermost layer of the meninges, while the pia mater is the delicate inner layer that lines the brain and spinal cord. In order from the outermost to innermost layer, the meninges are: dura mater, arachnoid mater, subarachnoid space, and pia mater.
Which of the 3 meninges is the strongest and thickest?Your dura mater is the outer, thick, strong membrane layer located directly under your skull and vertebral column.
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