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Thursday, December 1

  1. page Clinical considerations edited ... There are two types of hydrocephalus: non- communicating- Blockage of the CSF flow due to a b…
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    There are two types of hydrocephalus:
    non- communicating- Blockage of the CSF flow due to a blockage, resulting in increased intracranial pressure.
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    normal CSF pressure (NPH-pressure. This is called normal pressure hydrocephalus).hydrocephalus (NPH).
    Symptoms
    One of more of these symptoms may be experienced as a result of hyrocephalus:
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    urinary incontinence
    Imaging of the ventricular system
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    are safe and easy to use.
    Investigations
    Lumbar puncture {19078.jpg}
    (view changes)
    1:51 pm
  2. page Embryology edited Here's a quick introduction and brief overview of the embryology of the brain. It will help give yo…
    Here's a quick introduction and brief overview of the embryology of the brain. It will help give you an undertsanding of where the ventricles come from and how each part of the brain has developed.
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    Embryology of the brain and CSF
    The nervous system originates from the neural plate (beginning of 3rd week). Neural folds, lie lateral to the neural plate and as development continues they lengthen and fold in to meet in the midline and fuse, creating a tube called the neural tube. This process is called neurulation. The lumen of the neural tube communicates freely with the amniotic cavity. Fusion of the neural folds is initiated in the cervical region and then spreads in rostral and caudal directions, leaving an opening at either end of the tube called the rostral and caudal neuropores. {Capture_1.PNG} Somite pairs from the 4th pair rostrally will develop to produce the future brain. The somites from the 4th pair caudally will become the spinal cord. Rostral and caudal neuropores gradually begin to close in the 3rd week, with the rostral neuropore closure occurs two days before the caudal. The rostral neuropore and fusion of the neural folds in the cranial region create expanded regions called brain vesicles that go on to form the:
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    Mesencephalon (midbrain)
    Rhombencephalon (hind brain)
    {Capture_2.PNG}
    During the development of the spinal cord, further growth lateral to the neural tube forms a ventral and dorsal thickening, known as basal plates and alar plates, respectively. The basal plates contain ventral motor cells and gather in the ventral horn of the spinal cord, where as the alar plates found in the dorsal horn of the spinal cord have sensory cells. The sulcus limitans marks the junction between the two neural plates.
    In the brain, alar and basal plates are only present in the Mesencephalon (midbrain) and the Rhombencephalon (hind brain).
    {Capture_3.PNG} Hind brainHindbrain consists of
    Metencephalon – pons and cerebellum (Pontine flexure separates the two regions of the hind brain)
    ConsistsThe Hindbrain consists of two
    Somatic efferent - these form the nucleus of the abducens nerve.
    specialSpecial visceral efferent-
    General visceral efferent- these innervate the submandicular and sublingual glands.
    The alar plates form three groups of sensory nuclei:
    somatic afferent-Somatic afferent - receives sensory
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    vestibulocochlear complex
    special

    Special
    visceral afferent
    general

    General
    visceral afferent
    {Capture_4.PNG}
    Myelencephalon – medulla oblongata
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    1:48 pm
  3. 12:55 pm
  4. page References edited ... Clinical Neuroanatomy 26th Edition S. G. Waxman McGraw Hill Lange 2010 Clinical neuroanatomy …
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    Clinical Neuroanatomy 26th Edition S. G. Waxman McGraw Hill Lange 2010
    Clinical neuroanatomy 7th edition R. S. Snell Wolters Klluwer Health 2010
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    2nd Edition R. L. Drake, A. W. Vogl, A.W. M. Mitchell Churchill Livingstone 2010
    Clinically Orientated Anatomy 6th Edition K. L. Moore, A. F. Dalley, A. M. R. Agur Wolters Kluwer 2010
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    12:30 pm
  5. page cerebrospinal fluid edited Cerebrospinal Fluid Where {CAp1.PNG} Where does it ... it do? Cerebrospinal fluid (CS…

    Cerebrospinal Fluid
    Where
    {CAp1.PNG}
    Where
    does it
    ...
    it do?
    Cerebrospinal fluid (CSF) is a clear, acellular fluid secreted by the choroid plexus of the lateral, third and fourth ventricles. In adults around 500ml of CSF is produced daily. It bathes the brain and the spinal cord, protecting against trauma. It prevents compression of nearby cranial nerve roots and vessels by the brain and the spinal cord. It also supplies nutrients to the brain and spinal cord and removes waste products.
    Where does it go?
    CSF flows from the lateral ventricles to the third ventricle via the interventricular foramina and then into the fourth ventricle through the cerebral aqueduct. Some CSF enters the subarachnoid space via the median and lateral apertures, however most gathers in subarachnoid cisterns, which are widened areas of the subarachnoid space.
    {ca2.PNG}
    CSF then finds it way into the venous system by passing through processes called arachnoid granulations which extend from the subarachnoid space into the superior sagittal dural sinus. The size and number of arachnoid granulations increase with age. CSF is absorbed into the venous system when the pressure of the CSF is higher than that of the venous pressure. Normally a balance is maintained between production and reabsorption of the CSF. Water, gases and lipid- soluble molecules from the blood can pass into the cerebrospinal fluid, however large molecules like protein can not.
    {cap3.PNG}
    Pressure
    CSF pressure is measured in mm of water and its normal range is within 70- 180. Respiration and contraction of the heart can alter this slightly. A rise in CSF pressure can occur due to and increase in:
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    12:27 pm
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  7. file ca2.PNG uploaded
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  8. file Capture_2.PNG uploaded
    12:21 pm

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