SPINAL CORD by 7m4ysl36

VIEWS: 51 PAGES: 37

									   Beginning:
   At the foramen magnum as a
    continuation of
    the
   Medulla Oblongata of the
    brain.
   Shape:
   Cylindrical.
   Length:
   About (45) cm.
   Occupies:
   Upper 2/3 of the vertebral
    (spinal) canal of the vertebral
    column.
   (1) Up till the 3rd month of
    Fetal Life:
   The spinal cord occupies the
    Entire Length of the
    vertebral canal.
   (2) At birth :
   It terminates at the level of
    L3.
   (3) Children :
   It ends at the Upper
    Border of the 3rd
    Lumbar vertebra.
   (4) Adults :
   It terminates at the
    Intervertebral disc (1st-
    2nd ) Lumbar vertebrae.
  Cervical:
(C3- T1) Segments.
 For the Brachial
  Plexus.
Lumbar:
(L1- S3) Segments.
 For the
 Lumbar and Sacral
  Plexuses.
   Conus Medullaris:
   A conical termination
    Caudal to the Lumbar
    Enlargement.
   FilumTerminale:
   A filament of connective
    tissue arises from the tip
    of the conus.
   It is attached to the 1st
    Coccygeal Vertebra.

   Anterior:
   Deep Anterior
    (Ventral)
   Median Fissure.
    Posterior:
   Shallow Posterior
   Median Sulcus.
   The Spinal Cord
    receives
   Information from
    and Controls the
    Movement of the
    Trunk and Limbs.
   It has (31) paired
    Spinal Nerves.
   Two linear series (6-8) of
    Nerve Fascicles are
    attached to the
    Dorsolateral and
    Ventrolateral aspects of
    the cord.
    The Fascicles coalesce to
    form Dorsal and Ventral
    Nerve Roots.
   The Roots pass to
    their corresponding
    Inter vertebral
    Foramena.
   Near which they
    join to form the
    Spinal Nerve
    Proper.
   Carry:
   Primary Afferent
    Neurons from the
    peripheral sensory
    receptors to the
    spinal cord and brain
    stem.
   Their cell bodies are
    in the Dorsal Root
    Ganglia.
   Carry :
   1.Efferent neurons
    (Lower Motor Neurons)
   Their cell bodies are
    located in the Spinal
    Gray matter.
   2.Preganglionic
    Autonomic neurons.
   Spinal Nerves are
    Mixed.
   Contain:
   Both Afferent and
    Efferent fibers.
   Each spinal nerve is
    divided into
   Dorsal and Ventral
    Rami.
   Dorsal Ramus :
   Thin.
   Supplies muscles and skin
    of the back.
   Ventral Ramus :
   Larger.
   Supplies muscles and skin
    of the Front of the body
    and limbs.
   Connected to the
    Sympathetic Chain by the
   The spinal cord is
    Segmented.
   In the Living
   The approximate level of
    the segments is
    identified by the
    Posterior Spinous
    Process of the vertebrae.
   Cervical Segments:
   One spine Higher than their
    corresponding vertebrae.
   C7 Segment is adjacent to
    C6 Vertebra.
   Thoracic segments :
   Two spines Higher .
   Lumbar segments :
   Three- Four spines Higher.
   Cervical Region :
   Cervical segments lie
    adjacent to their
    corresponding Vertebral
    Bodies.
   1-7 C : Above the
    Upper Seven
    Cervical Vertebrae.
   C8 : Below 7th
    Cervical Vertebra.
   T1 and the rest of
    the nerves: Below
    their Corresponding
    Vertebrae.
   The Lumbar and Sacral
    nerves take an Oblique
    Course to reach the
    intervertebral
    foramina.
   The resulting leash of
    nerve roots forms the
    Cauda Equina.
   Pia Mater
   The inner most layer.
   A delicate ,vascular
    membrane.
   It is Closely applied to
    the surface of the
    spinal cord.
   It extends inferiorly as
    the Filum Terminale.
   A flat membrane formed
    from Pia Mater.
   Extension:
   Along a midway line
    between the dorsal and
    ventral nerve roots.
   Laterally to adhere to
    the Arachnoid and Dura.
   The spinal cord is
    suspended in the middle
    of the dural sheath.
   Arachnoid:
   A a fibrous membrane.
   It Loosely covers the
    spinal cord.
   Dura:
   A dense, strong fibrous
    membrane.
   It is continuous
    superiorly with the
    Meningeal layer of the
    Cranial Dura.

   They extend along
    Each Nerve Root and
    become continuous
    with its Epineurium.
   Inferiorly
   They extend to the
    2nd sacral vertebra.
   Epidural
   Separates Dural Sheath from
    the Vertebral Canal.
   Contains the Internal
    Vertebral Venous Plexus.
    Subdural
   A thin space.
   Separates Dura from
    Arachnoid.
   Subarachnoid
   Contains Cerebro
    Spinal Fluid.
   Terminates
   At the level of S2
   Held in position by :
   Laterally : Denticulate
    Ligament.
   Inferiorly : Filum
    Terminale.
   The spinal cord is
    Cushioned against
    Trauma by:
    Cerebrospinal Fluid.
   Site :
   Subarachnoid Space
    (L2-L3 or L3 –L4).
   Not Allowed in Children.
   Indications:
   1. Diagnostic purposes.
   2. Radiological study
    (Myelography).
   Injection of
    Anaesthetics into
    the Epidural Space
    It is for Surgical
    Procedures as in
    Labour.
   1. Anterior spinal
    artery.
   2. Posterior
    spinal Arteries.
   3. Radicular
    Arteries.
A single Y shaped artery.
Arises from :Vertebral artery
  at the level of the medulla.
 Supplies the cord at the
  Cervical Level.
 It is most vulnerable in the
  anterior part of the cord
  particularly in the Thoracic
  Segment.
 Its Occlusion causes Acute
  Thoracic Syndrome with
  Paraplegia and
  Incontinence.
   Two arteries.
   Arise from
   . Vertebral Or
   Posterior Inferior
    Cerebellar arteries.
   Spinal Arteries (Anterior
    &Posterior) are
    Insufficient alone to
    supply the cord Below
    the Cervical Level.
   Origin from following
    arteries :
   1. Ascending cervical
    2. Intercostal.
   3. Lumbar.
   They share in the
    arterial supply of the
    cord Below the Cervical
    Level.
   They Anastomose freely
    with the Spinal
    Arteries.
   Artery of Adamkiewicz.
   It may arise from:
    Intercostal or Lumbar
    arteries.
   It supplies
   Lower half of the spinal
    cord (T8 –L3).
   These are Vulnerable
    Segments.
   Occlusion of the artery
    may cause Muscle
    weakness and Paralysis.
   Six Longitudinal
    Interconnecting Venous
    Channels.
   (1) Anterior and Posterior
    Spinal veins in the midline.
   (2) Anterolateral and
    Posterolateral paired veins
    situated near the lines of
    attachment of the
   Ventral and
   Dorsal roots.
   (3) Anterior and Posterior
    Radicular Veins.
   (4) Internal
    vertebral venous
    plexus in the
    Epidural Space.
   (5) External
    Vertebral Venous
    Plexus.
   (6) Ascending
    Lumbar, Azygos and
    Hemiazygos Veins.
   The spinal nerve roots can be
    injured by Compression of
    Prolapsed Intervertebral Discs
   It is manifested by:
   1. Paraesthesia (tingling
    sensations).
   2. Weakness and wasting of
    the muscles.
   3. Numbness of the skin
    corresponding to the
    dermatomal distribution.
   4. Loss of Tendon Reflexes.
   (A) Cervical
   Pain in the neck radiating to
    the arm and hand.
   (B) Lumbar
   1. Back pain.
   2. Sciatica ( radiation of
    pain into the legs) .
   A large Lumbosacral
    prolapsed disc can cause
    paralysis of the bladder and
    incontinence.

								
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