Meninges Notes PDF
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These notes provide an overview of the meninges layers, including Dura, Arachnoid, and Pia. It further details the spaces between them, like the subdural and subarachnoid spaces, which can be significant pathologically.
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Meninges Monday, September 9, 2024 9:27 AM - Layers ○ Dura ▪ Outermost layer connected to the skull □ ▪ 2 fused layers □ Periosteal layer Connected to skull □ Me...
Meninges Monday, September 9, 2024 9:27 AM - Layers ○ Dura ▪ Outermost layer connected to the skull □ ▪ 2 fused layers □ Periosteal layer Connected to skull □ Meningeal layer Connected to arachnoid Can create folds, aka dural reflections ◊ Creates falx cerebri & tentorium cerebelli ○ Arachnoid ▪ Middle layer ▪ Spider-like, attaches to inner dural layer ▪ Contain arachnoid granulations that are involved in reabsorption of CSF ▪ Arachnoid trabeculae connect arachnoid to pia mater □ ○ Pia ▪ Innermost layer ▪ Adheres tightly to brain Exam 1 Page 1 ▪ ○ - Spaces ○ Real spaces ▪ Exist under normal conditions ○ Potential spaces ▪ Becomes real space pathologically w/ accumulation of blood ○ Epidural space ▪ Potential space b/w skull & periosteal layer of dura ▪ Meningeal arteries run here (branches of external carotid arteries) □ Supplies dura ▪ Becomes real space via bleed in middle meningeal a. from fracture of temporal bone □ Results in epidural hematoma ○ Subdural space ▪ Potential space b/w dura & arachnoid ▪ Bridging veins drain cerebral hemispheres, travel in subdural space, drain into dural venous sinus ▪ Becomes real space via shear forces applied to the head causing a rupture of the bridging veins □ Results in venous hemorrhage in subdural space & subdural hematoma (generally) Acute subdural hematoma ◊ Following significant head trauma (e.g. shaken baby syndrome, brain contusion, subarachnoid hemorrhage) Chronic subdural hematoma ◊ Minimal/ no known history of trauma ◊ Weeks to occur, most common in elderly patients ○ Subarachnoid space ▪ It is a real space b/w arachnoid & pia Exam 1 Page 2 ▪ It is a real space b/w arachnoid & pia ▪ Filled w/ CSF ▪ Major arteries & veins suspended within arachnoid trabeculae ▪ Rupture of arterial aneurysm releases blood into subarachnoid space □ Aka subarachnoid hemorrhage This is when blood accumulated where CSF is □ Types Non-traumatic (spontaneous) ◊ Rupture of arterial aneurysm ◊ 'worst headache of my life' Traumatic ◊ Most common type ◊ Bleeding in subarachnoid space after cerebral contusions ○ Exam 1 Page 3
