spinal cord and Spinal nerves indepth ppt

Brief knowledge about spinal nerve

1. Spinal Cord
and
Spinal Nerves
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2. Spinal Cord
•Spinal cord a tubular
extension of the brain
distal to the medulla
oblongata
•It occupies the
vertebral canal
suspended in the
CSF and sorrounded
by the meninges.
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3. Vertebral
Column
& Meninges
Protective
Structures
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4. Spinal Cord
•Spinal cord extends
from the medulla
oblongata to the lower
border of L
1 vertebra
in adults.
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5. •Conus medullaris.

•Cauda equina.

•Filum terminale,
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6. Spinal Cord
•Structurally spinal cord can
be said to be made up of 31
slices (segments) bound
together to make one
cylindrical unit.
•Each connected to a pair of
spinal nerves.
•Ventral and Dorsal roots
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7. Cross Sectional Anatomy of the Spinal Cord
•Gray matter is in the core of the cord and surrounded
by white matter.
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8. •On section the gray matter of the spinal cord resembles
a butterfly.
•2 lateral gray masses connected by the gray
commissure.
•posterior or dorsal horns.
•anterior or ventral horns.
•lateral horns.
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9. Gray Matter
•Posterior horns contain
sensory neurons
•Anterior horns contains
the cell bodies of motor neurons.
–These cell bodies project their axons via the ventral
roots of the spinal cord to the skeletal muscles.
–The amount of ventral gray matter at a given level of
the spinal cord is proportional to the amount of
skeletal muscle innervated.
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10. Gray Matter
•Lateral horn
neurons are
sympathetic motor
neurons serving
visceral organs.
–Their axons also exit
via the ventral root.
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12. White Matter
•Myelinated nerve fibers.
•White matter on each side of the cord is divided into
columns or funiculi.
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13. Sensory and Motor Tracts
What is the purpose of knowing the position of the tracts?
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14. Spinal Nerves
•31 nerves
connecting the
spinal cord and
various body
regions.
•8 paired cervical
nerves
•12 paired thoracic
nerves
•5 paired lumbar
nerves
•5 paired sacral
nerves
•1 pair of coccygeal
nerves
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15. Spinal Nerves
•Each connects to the
spinal cord by 2 roots –
dorsal and ventral.
•Ventral roots are motor
while dorsal roots are
sensory.
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16. Spinal
Nerves
•The 2 roots join to
form a spinal
nerve prior to
exiting the
vertebral column.
•After emerging from its intervertebral foramen, a spinal nerve
will divide into a dorsal ramus, a ventral ramus, and a
meningeal branch that reenters and innervates the meninges
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17. •Motor fibres arise from the motor neurons in the
anterior gray horn
•Sensory fibres arise from the sensory neurons in the
dorsal root ganglion
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18. •Each ramus is mixed.
•Joined to the base of the ventral rami of spinal nerves in the
thoracic region are the rami communicantes.
•Dorsal rami supply the posterior body trunk whereas the thicker
ventral rami supply the rest of the body trunk and the limbs.
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22. Motor supply of Spinal cord
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23. Nerve Plexuses
•Except for T
2 to T
12, all ventral rami
branch extensively and join one another
lateral to the vertebral column forming
complicated nerve plexuses.
•W/i a plexus, fibers from different rami
crisscross each other and become
redistributed.
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26. Spinal Cord
•Spinal cord has two maintains
homoeostasis in 2 ways
–Through Nerve impulse propagation and
integration of information.
–By serving as an integrating centre for some
reflexes.
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27. Spinal Cord – Homoeostasis
1.Nerve impulse propagation and
integration of information.
–White matter: highways or electrical wires
for Nerve impulse propagation
–Gray matter: centre for integration of
information.
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28. Spinal Cord – Homoeostasis
2.Centre for integrating reflexes
Reflex: A reflex is a fast, automatic,
unplanned sequence of actions that
occur in response to a stimulus
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29. Types
•Spinal reflex – integration takes place in
spinal cord
•Cranial reflex – integration takes place in
brain stem.
•Somatic reflex – involves contraction of
skeletal muslce
•Autonomic reflex – not perceived
consciously. Targeted at smooth muscle,
cardiac muscle or a gland
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30. Reflex Arc
•The pathway followed by
nerve impulse to produce
a reflex is called a reflex
arc
•It has 5 functional
components
–Sensory receptor
–Sensory neuron
–Integrating centre
–Motor neuron
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31. Somatic reflexes
•The stretch reflex
•The tendon reflex
•The flexor (withdrawal reflex)
•The crossed extensor reflex

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35. Reflexes
•Reflexes may be
inborn or learned.
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36. •Reflexes may be monosynaptic
or polysynaptic.

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38. Muscle Spindle Reflex
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39. Golgi Tendon Reflex
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40. Autonomic Reflexes
•May be spinal (e.g.,
urination and defecation)
or cranial.
•The thalamus,
hypothalamus and brain
stem are in charge of
multiple reflexes – HR,
BP, breathing, eating,
osmotic balance,
temperature, vomiting,
gagging, sneezing.
•All are polysynaptic.
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42. •Reflexes provide information about the
health of the nervous system and can
greatly aid in the diagnosis of disease.
•Damage or Disease any where along the
reflex arc can cause a reflex to be absent
or abnormal
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43. •Patellar reflex (Knee jerk)
•Achilles reflex (Ankle jerk)
•Babinski’s sign
•Abdominal reflex
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44. Trauma to Spinal cord
•Causes
–Automobile accidents
–Falls
–Contact sports
–Diving
–Acts of violence
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45. Common sites of injury
•Cervical
•Lower thoracic
•Upper lumbar
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46. Result of the damage - paralysis
•Monoplegia
•Diplegia
•Paraplegia
•Hemiplegia
•Quadriplegia
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47. •Paraplegia
–R
x. Arg nit, Ars, Nux v.
•Hemiplegia
–R
x. Alum, Anac, Ars, Caust, Graph, Kali c,
Lach, Mur ac, Phos, Rhus t, Stann, Sulph ac.
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48. Complete transection
•Loss of all sensations and voluntary
movement below the level of the
transection
•The extent of the paralysis of skeletal
muscle depends on the level of the injury
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49. Functions retained
•C
1 – C
3: No function maintained from the
neck down; ventilator needed for breathing
•C
4 – C
5: Diaphragm, which allows
breathing
•C
6 – C
7: some arm and chest muscles,
which allows feeding and propelling wheel
chair
•T
1 – T
3: intact arm function
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50. Functions retained
•T
4– T
9: control of trunk above the
umbilicus
•T
10– L
1: most thigh muscles, which allows
walking with long leg braces
• L
1– L
2: most leg muscles which allows
walking with short braces


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51. Hemisection
•Brown-Sequard syndrome
–Loss of proprioception and touch sensation on
the same side as the injury
–Ipsilateral paralysis
–Loss of pain and temperature sensations
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52. Spinal shock
•Areflexia – loss of function
•Signs of spinal shock
–Slow heart rate
–Low blood pressure
–Flaccid paralysis of skeletal muscle
–Loss of somatic sensations
–Urinary bladder dysfunction
•R
x
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53. Spinal Cord Compression
•Causes of spinal cord compression
–Injuries
–Extra dural
•Herniation of intervertebral disc
•Tubercular infection of the vertebrae
•Tumors of the vertebrae
•Leukemic deposits
•Extradural abscess
–Intra dural
•Primary tumors of the spinal cord such as gliomas
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54. Spinal Cord Compression
•Pressure on spinal arteries causes
ischemia of the spinal cord with
degeneration of nerve cells and their fibres
•Pressure on the veins causes edema of
the spinal cord with interference in the
function of the neurons
•Pressure on the white and gray matter of
the spinal cord causes interference in the
nerve conduction.
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55. Spinal Cord Compression
•Clinical signs
–Pain. Local pain in the vertebra involved or radiating
pain along the distribution of one or more spinal nerve
roots.
•Pain < by coughing, sneezing. < at night.
–Involvement of the anterior gray column motor cells at
the level of lesion cause complete or partial paralysis
with loss of tone and wasting
–Muscular weakness and increased muscle tone,
increased tendon reflexes below the lesion and
extensor plantar response.
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56. Spinal Cord Compression
•Clinical signs
–Lesion of the posterior white column causes
loss of muscle joint sense, vibration and
tactile discrimination below the level of the
lesion on the same side.
–Involvement of lateral spinothalamic tract
causes loss of pain and temperature sense on
the opposite side of the lesion.
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57. •Affects the posterior
root ganglia
•Pain
•Discoloration of skin
•Characteristic line of
blisters
Shingles (Herpes zoster)
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58. Shingles (Herpes zoster)
Affects the posterior root
ganglion.
Homoeopathic
therapeutics…
Erruptions: Herpes zoster
– All-s, Ars alb, Lach,
Merc, Nat.carb, Sepia,
Rhu.tox and Zinc.
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59. Poliomyelitis
•Affects the motor neurons
in the anterior horn and in
the brain stem.
•Signs and symptoms
–Fever, severe headache, a
stiff neck and back
–Deep muscle pain and
weakness
–Loss of somatic reflexes
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61. Poliomyelitis
•Poliomyelitis infection – Acon, Calc, Caust,
Gels, Latherus, Plb, Rhus tox.
–Neuralgic pain after – Rhus tox
–Paralysis of diaphragm with – Cupr, Opium
and Sil.
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