MENINGES & CEREBRALSPINAL FLUID CIRCULATION
Terms
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- cerebral spinal fluid produced by
- choroid plexus of the four ventricles.
- CSF function
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1) structural support
2) cushioning to the brain and spinal cord. - Leptomeninges is composed of the:
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1. Pia mater
2. Arachnoid - MENINGEAL SPACES
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A.Epidural Space
1.Cranium - potential space
2.Spinal cord - real space
B. Subdural space - Cisterns
- “Large†areas in the subarachnoid space
- WHAT ARE THE THREE (3) MAJOR TYPES OF INTRACRANINAL BLEEDING?
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1.Subarachnoid Hemorrhage
2.Subdural Hemorrhage
3.Extradural (Epidural) Hemorrhage - Subarachnoid Hemorrhage
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-Common in trauma patients. Unconscious > 1 hr.
-Often caused by ruptured arterial aneurysm at base of brain.
-Sudden onset, severe headache, stiff neck.
-Signs of meningeal irritation. - Subdural Hemorrhage
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-Minor to severe head trauma.
-Usually subdural veins rupture.
Fast or slow?
-Can cross suture lines.
-Common in alcoholics - Extradural (Epidural) Hemorrhage
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-Usually follows traumatic rupture of middle meningeal artery or vein.
-Fracture of squamous temporal bone results in cut vessel.
-Can cross midline but not suture lines. - WHAT HAPPENS WITH A BUILD UP OF CSF?
- Hydrocephalus
- Hydrocephalus - 2 causes
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1. OBSTRUCTIVE HYDROCEPHALUS
2. COMMUNICATING HYDROCEPHALUS - OBSTRUCTIVE HYDROCEPHALUS
- Blockage in system or around the brain.
- OBSTRUCTIVE HYDROCEPHALUS: Possible causes?
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Tumors, hemorrhage, infections, and
genetic - Where are the INSIDE “choke points� OUTSIDE “choke points�
- ??
- COMMUNICATING HYDROCEPHALUS: Causes
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A. Over production of CSF.
B. Impaired absorption by arachnoid villi.
C. Venus insufficiency. - Could blood in CSF affect the villi? Meningitis?
- ??
- Dura mater components
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1. Periosteal layer
2. Meningeal layer
3. Sinuses - Meningeal layer components
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a. Falx cerebri and cerebelli
b. Tentorium cerebelli
c. Diaphragma sellae - Cerebrospinal fluid flow
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Choroid plexus of lateral ventricles to
Interventricular foramen (of Monro) to
3rd ventricle to
Cerebral aqueduct (of Sylvius) to
4th Ventricle to
Median and lateral apertures (Foramina of Magendie and Luschka) out - 3 Anterior aspect subarachnoid cisterns
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1. Chiasmatic
2. Interpeduncular
3. Pontine - 2 Posterior aspect subarachnoid cisterns
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1. Superior
2. Cerebellomedullary (Magna) - 1 lateral aspect subarachnoid cistern
- lateral cistern - In the area of the lateral sulcus
- 1 Spinal area subarachnoid cistern
- lumbar cistern
- Where is a lumbar puncture performed
- lumbar cistern
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HOW CAN INFECTIONS IN THE
CRANIAL SINUSES, CRANIAL BONES, FETAL MONITORING, AND BRAIN SURGERY LEAD TO CSF PROBLEMS ? - Emissary veins