SPINAL CORD

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SPINAL CORD

• CLINICAL APPLICATIONS

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NERVE TRACTS
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Fasciculus cuneatus, gracilis

• Sensory neurons extend from receptors in skin
  into spinal cord and end in brain.
• Receptors detect movement across skin (velocity),
  pressure, and vibration.
• Proprioceptors in joints sense position of limbs.
• Gracilis medial from lower levels
• Cuneatus lateral from higher levels

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Sensory Pathways
F. Cuneatus C2 (most lateral fiber)
F. Cuneatus T6 (most medial fiber)
F. Gracilis T7 (most lateral fiber)
F. Gracilis L5 (most medial fiber)
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What is the effect of a lesion.

• A lesion in the peripheral spinal nerve prevents
  the transfer of information from an entire
  dermatome.
• A lesion in the spinal cord causes different
  effects depending on location, neurons.
• Lesion at C1
• Lesion at L3

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Other lesions in dorsal column.

• Astereognosia, (the inability to recognize
  objects or forms by touch.) Put a key in your
  hand with your eyes closed and you can identify
  it as a key. Agraphesthesia (inability to
  recognize letters, numbers, etc., drawn on the
  skin). The loss of conscious joint position sense
  in the legs (lesion involving fasciculus
  gracilis) causes ataxia or incoordination of
  gait. Such incoordination results in the
  inability of a patient to stand with their feet
  together, arms outstretched. This is called a
  positive Romberg sign. In the upper extremity,
  such ataxia results in clumsiness. Paresthesia
  is tingling and numbness resulting from
  irritation of the fibers as they die.

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Spinal Cord Injury

• Recovery from spinal cord injury is fairly
  predictable. Persons with a complete injury by
  neurologic examination generally are not expected
  to make any significant recovery except some
  improvement in motor strength in the zone of
  injury. Recovery for persons with an incomplete
  injury is less predictable and most recovery
  occurs within the first six months however, some
  additional neurologic recovery may take place up
  to 18 months after injury.

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Spina Bifida
Spina bifida is caused by the failure of the
bones of the spine to fuse during early fetal
development. It occurs with or without the
involvement of the brain, nerves or meninges.
Spina bifida includes deformities of certain
parts of the vertebrae,the spinous process and
vertebral arch.
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Types of Spina Bifida
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Spina Bifida Occulta
Since there is no opening to the skin, spina
bifida occulta can only be seen on x-ray or MRI.
Dimpling of the skin or a hairy patch at the
base of the spine may indicate spina bifida.
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Spina Bifida Occulta
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Types of Open Spina Bifida
Myelomeningocele
Meningocele
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Meningocele
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Myelomeningocele
Marieb and Hoehn, 2007. Human Anatomy
Physiology, Benjamin Cummings.
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End of Spinal Cord
Location of lumbar puncture an area between the
end of the spinal cord and the end of the dural
sac where a needle can be inserted safely to
withdraw CSF.
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Lumbar Puncture
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Transverse Section

• Vertebral artery 2. Vertebral veins 4. 3rd
• cervical spinal ganglion 5.Ventral (anterior)
• median fissure 6. Subdural space 10. Arachnoid
• mater 11. Dura mater 12. Epidural fat

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Flexion of Spine for Puncture
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CSF for Lab Analysis
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REFLEX ARC
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Peripheral Nerves
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Peripheral Nerves