anatomy of the spinal cord structure of the spinal cord tracts of the spinal cord
DESCRIPTION
Anatomy of the Spinal Cord Structure of the spinal cord Tracts of the spinal cord Spinal cord syndromes. Spinal Cord. - Comparable to Input-Output (IO) System of the Computer - Spinal Nerve (C8, T12, L5, S5, Cx1) - Segmental Structure of Neural Tube Origin. Spinal segment - PowerPoint PPT PresentationTRANSCRIPT
Anatomy of the Spinal Cord Anatomy of the Spinal Cord
Structure of the spinal cordStructure of the spinal cord
Tracts of the spinal cordTracts of the spinal cord
Spinal cord syndromes Spinal cord syndromes
Anatomy of the Spinal Cord Anatomy of the Spinal Cord
Structure of the spinal cordStructure of the spinal cord
Tracts of the spinal cordTracts of the spinal cord
Spinal cord syndromes Spinal cord syndromes
- Comparable to- Comparable to Input-Output (IO) System of the ComputerInput-Output (IO) System of the Computer
- Spinal Nerve (C8, T12, L5, S5, Cx1)- Spinal Nerve (C8, T12, L5, S5, Cx1)
- Segmental Structure of Neural Tube Origin- Segmental Structure of Neural Tube Origin
- Comparable to- Comparable to Input-Output (IO) System of the ComputerInput-Output (IO) System of the Computer
- Spinal Nerve (C8, T12, L5, S5, Cx1)- Spinal Nerve (C8, T12, L5, S5, Cx1)
- Segmental Structure of Neural Tube Origin- Segmental Structure of Neural Tube Origin
Spinal CordSpinal CordSpinal CordSpinal Cord
Spinal segment Spinal segment
C8, T12, L5, S5, Cx1C8, T12, L5, S5, Cx1
Anterior (Ventral) RootAnterior (Ventral) RootPosterior (Dorsal) RootPosterior (Dorsal) Root Dorsal Root (Spinal) GanglionDorsal Root (Spinal) Ganglion
Root - RootletsRoot - Rootlets
Conus Medullaris Conus Medullaris (L1-2)(L1-2)
Spinomedullary JunctionSpinomedullary Junction - Foramen Magnum, Pyramidal decussation, C1 ventral root
EnlargementsEnlargements - cervical (C5-T1) & lumbosacral (L1-L4)
Longitudinal FissuresLongitudinal Fissures - anterior median fissure - anterolateral fissure - posterior median sulcus - posterolateral sulcus
Conus Medullaris Conus Medullaris (L1-2)(L1-2)
Spinomedullary JunctionSpinomedullary Junction - Foramen Magnum, Pyramidal decussation, C1 ventral root
EnlargementsEnlargements - cervical (C5-T1) & lumbosacral (L1-L4)
Longitudinal FissuresLongitudinal Fissures - anterior median fissure - anterolateral fissure - posterior median sulcus - posterolateral sulcus
Spinal Cord Spinal Cord External FigureExternal Figure Spinal Cord Spinal Cord External FigureExternal Figure
Conus Medullaris Conus Medullaris (L1-2)(L1-2)
Cauda EquinaCauda Equina
Anterior median fissureAnterior median fissureAnterolateral fissureAnterolateral fissure
Posterior Posterior median sulcusmedian sulcus
PosterolateralPosterolateral
sulcussulcus
Posterior Posterior intermediate intermediate sulcussulcus
FasciculusFasciculus
cuneatuscuneatus
FasciculusFasciculus
gracilisgracilis
Posterior surface of the spinal cordPosterior surface of the spinal cord
Periosteum of VertebraPeriosteum of Vertebra
- - Epidural Space Epidural Space ----------------- ----------------- epidural anesthesiaepidural anesthesia
Dura Mater Spinalis Dura Mater Spinalis
Arachnoid MembraneArachnoid Membrane - - Subarachnoid Space --------Subarachnoid Space -------- Lumbar Puncture Lumbar Puncture
Spinal AnesthesiaSpinal Anesthesia
Pia Mater SpinalisPia Mater Spinalis - Denticulate Ligament- Denticulate Ligament --------- --------- CordotomyCordotomy
- Filum Terminale- Filum Terminale
Periosteum of VertebraPeriosteum of Vertebra
- - Epidural Space Epidural Space ----------------- ----------------- epidural anesthesiaepidural anesthesia
Dura Mater Spinalis Dura Mater Spinalis
Arachnoid MembraneArachnoid Membrane - - Subarachnoid Space --------Subarachnoid Space -------- Lumbar Puncture Lumbar Puncture
Spinal AnesthesiaSpinal Anesthesia
Pia Mater SpinalisPia Mater Spinalis - Denticulate Ligament- Denticulate Ligament --------- --------- CordotomyCordotomy
- Filum Terminale- Filum Terminale
Spinal Cord MeningesSpinal Cord Meninges Spinal Cord MeningesSpinal Cord Meninges
Meninges of Meninges of the spinal cordthe spinal cord
• Dura materDura mater• Arachnoid membraneArachnoid membrane• Pia materPia mater
Denticulate ligamentDenticulate ligament
- specilization of the pia mater- specilization of the pia mater
- landmark for cordotomy- landmark for cordotomy
Meninges of the spinal cordMeninges of the spinal cord
Meninges of the spinal cordMeninges of the spinal cord
Lumbar Puncture – lumbar (terminal) cisternLumbar Puncture – lumbar (terminal) cistern
Arterial SupplyArterial Supply
- Spinal Arteries- Spinal Arteries
Anterior (1) & Posterior (2) Spinal ArteryAnterior (1) & Posterior (2) Spinal Artery
from from Vertebral arteryVertebral artery
- Radicular Arteries ----- Segmental arteries- Radicular Arteries ----- Segmental arteries
from from Vertebral, Ascending Cervical, Intercostal andVertebral, Ascending Cervical, Intercostal and
Lumbar Artery Lumbar Artery
Venous DrainageVenous Drainage - - Longitudinal & Radicular Veins Longitudinal & Radicular Veins
toto Intervertebral veins Intervertebral veins ---- to ---- to Internal Vertebral Venous PlexusInternal Vertebral Venous Plexus
to to external vertebral venous plexus external vertebral venous plexus ---- to ---- to segmental veinssegmental veins
Arterial SupplyArterial Supply
- Spinal Arteries- Spinal Arteries
Anterior (1) & Posterior (2) Spinal ArteryAnterior (1) & Posterior (2) Spinal Artery
from from Vertebral arteryVertebral artery
- Radicular Arteries ----- Segmental arteries- Radicular Arteries ----- Segmental arteries
from from Vertebral, Ascending Cervical, Intercostal andVertebral, Ascending Cervical, Intercostal and
Lumbar Artery Lumbar Artery
Venous DrainageVenous Drainage - - Longitudinal & Radicular Veins Longitudinal & Radicular Veins
toto Intervertebral veins Intervertebral veins ---- to ---- to Internal Vertebral Venous PlexusInternal Vertebral Venous Plexus
to to external vertebral venous plexus external vertebral venous plexus ---- to ---- to segmental veinssegmental veins
Spinal Cord Spinal Cord Vascular SupplyVascular Supply Spinal Cord Spinal Cord Vascular SupplyVascular Supply
anterior spinal arteryanterior spinal artery segmental arteries segmental arteries
5. Adamkiwicz artery5. Adamkiwicz artery
White MatterWhite Matter Anterior Funiculus (Anterior White Column)Anterior Funiculus (Anterior White Column)
Posterior Funiculus (Posterior White Column)Posterior Funiculus (Posterior White Column) Fasciculus Gracilis & Fasciculus CuneatusFasciculus Gracilis & Fasciculus Cuneatus
Lateral Funiculus (Lateral White Column)Lateral Funiculus (Lateral White Column)
Gray MatterGray Matter Anterior Horn ------------Anterior Horn ------------------ motormotor
Posterior Horn --------------Posterior Horn -------------- sensorysensory
Lateral Horn -----------------Lateral Horn ----------------- autonomic (sympathetic)autonomic (sympathetic)
Gray Commissure -------- Gray Commissure -------- anterior and posterior anterior and posterior
White MatterWhite Matter Anterior Funiculus (Anterior White Column)Anterior Funiculus (Anterior White Column)
Posterior Funiculus (Posterior White Column)Posterior Funiculus (Posterior White Column) Fasciculus Gracilis & Fasciculus CuneatusFasciculus Gracilis & Fasciculus Cuneatus
Lateral Funiculus (Lateral White Column)Lateral Funiculus (Lateral White Column)
Gray MatterGray Matter Anterior Horn ------------Anterior Horn ------------------ motormotor
Posterior Horn --------------Posterior Horn -------------- sensorysensory
Lateral Horn -----------------Lateral Horn ----------------- autonomic (sympathetic)autonomic (sympathetic)
Gray Commissure -------- Gray Commissure -------- anterior and posterior anterior and posterior
Spinal Cord Spinal Cord Internal StructureInternal Structure Spinal Cord Spinal Cord Internal StructureInternal Structure
• Resembles a butterfly.
• 2 lateral gray masses connected by the gray
commissure.
• Posterior projections are the posterior or dorsal horns.
• Anterior projections are the anterior or ventral horns.
• In the thoracic and lumbar cord, there also exist lateral horns.
Gray Matter
• Posterior horns contain
interneurons.
• Anterior horns contain some
interneurons as well as 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.
Gray Matter
• Lateral horn neurons are sympathetic motor neurons serving visceral organs.
– Their axons also exit via the ventral root.
• Afferent sensory fibers carrying info from peripheral receptors form the dorsal roots of the spinal cord. The somata of these sensory fibers are found in an enlargement known as a dorsal root ganglion.
• The dorsal and ventral roots fuse to form spinal nerves.
1. posterior horn 1. posterior horn
2. anterior horn 2. anterior horn
3. intermediate zone 3. intermediate zone
(intermediate gray) (intermediate gray)
4. lateral horn 4. lateral horn
5. posterior funiculus5. posterior funiculus
6. anterior funiculus6. anterior funiculus
7. lateral funiculus 7. lateral funiculus
8. Lissauer's tract 8. Lissauer's tract
9. anterior median 9. anterior median
fissure fissure
10. posterior median 10. posterior median
sulcus sulcus
11. anterolateral 11. anterolateral
sulcus sulcus
12. posterolateral 12. posterolateral
sulcus sulcus
13. Posterior13. Posterior
intermediate intermediate sulcus sulcus
cervical enlargement (C8)cervical enlargement (C8) thoracic cord (T8) thoracic cord (T8)
lumbal enlargement (L3)lumbal enlargement (L3) sacral cord (S1) sacral cord (S1)
Principles of Cord OrganizationPrinciples of Cord Organization
1) Longitudinal Arrangement1) Longitudinal Arrangement Fibers (White Matter) ------------- White ColumnFibers (White Matter) ------------- White Column
Cell Groups (Gray Matter) ------- Gray ColumnCell Groups (Gray Matter) ------- Gray Column
2) Transverse Arrangement2) Transverse Arrangement Afferent & Efferent FibersAfferent & Efferent Fibers
Crossing (Commissural and Decussating) FibersCrossing (Commissural and Decussating) Fibers
3) Somatotopical Arrangement3) Somatotopical Arrangement
Principles of Cord OrganizationPrinciples of Cord Organization
1) Longitudinal Arrangement1) Longitudinal Arrangement Fibers (White Matter) ------------- White ColumnFibers (White Matter) ------------- White Column
Cell Groups (Gray Matter) ------- Gray ColumnCell Groups (Gray Matter) ------- Gray Column
2) Transverse Arrangement2) Transverse Arrangement Afferent & Efferent FibersAfferent & Efferent Fibers
Crossing (Commissural and Decussating) FibersCrossing (Commissural and Decussating) Fibers
3) Somatotopical Arrangement3) Somatotopical Arrangement
Spinal Cord Spinal Cord Internal StructureInternal Structure Spinal Cord Spinal Cord Internal StructureInternal Structure
Columnnar arrangement somatotopical arrangementColumnnar arrangement somatotopical arrangement
Laminae of RexedLaminae of Rexed
Lamina I ---------- posteromarginal nucleusLamina I ---------- posteromarginal nucleus
Lamina II ---------- Lamina II ---------- substantia gelatinosa of Rolandosubstantia gelatinosa of Rolando
Lamina III, IV ----- nucleus propriusLamina III, IV ----- nucleus proprius
Lamina V, VILamina V, VI
Lamina VII --------- intermediate grayLamina VII --------- intermediate gray
intermediolateral cell column (ILM)intermediolateral cell column (ILM)
Clarke’s column (Nucleus dorsalis)Clarke’s column (Nucleus dorsalis) intermediomedial cell column (IMM)intermediomedial cell column (IMM)
Lamina VIIILamina VIII
Lamina IX ---------- Lamina IX ---------- anterior horn (motor) cellanterior horn (motor) cell
Lamina X ----------- gray commissureLamina X ----------- gray commissure
Laminae of RexedLaminae of Rexed
Lamina I ---------- posteromarginal nucleusLamina I ---------- posteromarginal nucleus
Lamina II ---------- Lamina II ---------- substantia gelatinosa of Rolandosubstantia gelatinosa of Rolando
Lamina III, IV ----- nucleus propriusLamina III, IV ----- nucleus proprius
Lamina V, VILamina V, VI
Lamina VII --------- intermediate grayLamina VII --------- intermediate gray
intermediolateral cell column (ILM)intermediolateral cell column (ILM)
Clarke’s column (Nucleus dorsalis)Clarke’s column (Nucleus dorsalis) intermediomedial cell column (IMM)intermediomedial cell column (IMM)
Lamina VIIILamina VIII
Lamina IX ---------- Lamina IX ---------- anterior horn (motor) cellanterior horn (motor) cell
Lamina X ----------- gray commissureLamina X ----------- gray commissure
Spinal CordSpinal Cord Internal StructureInternal Structure Spinal CordSpinal Cord Internal StructureInternal Structure
Laminae of RexedLaminae of Rexed
White Matter• Myelinated nerve fibers.• Allows for communication btwn the brain and spinal cord or btwn different regions of
the spinal cord.• White matter on each side of the cord is divided into columns or funiculi.
– Typically, they are ascending or descending.» What does that mean?
Ascending TractsAscending Tracts
Modality: Modality: Touch, Pain, Temperature, KinesthesiaTouch, Pain, Temperature, Kinesthesia
Receptor: Receptor: Exteroceptor, Interoceptor, ProprioceptorExteroceptor, Interoceptor, Proprioceptor
Primary Neuron: Primary Neuron: Dorsal Root Ganglion (Spinal Ganglion)Dorsal Root Ganglion (Spinal Ganglion)
Secondary Neuron: Secondary Neuron: Spinal Cord or Brain StemSpinal Cord or Brain Stem
(Tertiary Neuron): (Tertiary Neuron): Thalamus (Ventrobasal Nuclear Complex)Thalamus (Ventrobasal Nuclear Complex)
Termination: Termination: Cerebral Cortex, Cerebellar Cortex, orCerebral Cortex, Cerebellar Cortex, or
Brain StemBrain Stem
Ascending TractsAscending Tracts
Modality: Modality: Touch, Pain, Temperature, KinesthesiaTouch, Pain, Temperature, Kinesthesia
Receptor: Receptor: Exteroceptor, Interoceptor, ProprioceptorExteroceptor, Interoceptor, Proprioceptor
Primary Neuron: Primary Neuron: Dorsal Root Ganglion (Spinal Ganglion)Dorsal Root Ganglion (Spinal Ganglion)
Secondary Neuron: Secondary Neuron: Spinal Cord or Brain StemSpinal Cord or Brain Stem
(Tertiary Neuron): (Tertiary Neuron): Thalamus (Ventrobasal Nuclear Complex)Thalamus (Ventrobasal Nuclear Complex)
Termination: Termination: Cerebral Cortex, Cerebellar Cortex, orCerebral Cortex, Cerebellar Cortex, or
Brain StemBrain Stem
Spinal Cord TractsSpinal Cord Tracts Spinal Cord TractsSpinal Cord Tracts
Ascending TractsAscending Tracts
Posterior White Column-Medial Lemniscal PathwayPosterior White Column-Medial Lemniscal Pathway
Spinothalamic TractSpinothalamic Tract
Spinoreticular or Spinoreticulothalamic TractSpinoreticular or Spinoreticulothalamic Tract
Spinocerebellar TractSpinocerebellar Tract Spinomedullothalamic TractSpinomedullothalamic Tract
Cervicothalamic or Spinocervicothalamic Tract Cervicothalamic or Spinocervicothalamic Tract
Spino-olivary TractSpino-olivary Tract
Spinotectal TractSpinotectal Tract
Ascending TractsAscending Tracts
Posterior White Column-Medial Lemniscal PathwayPosterior White Column-Medial Lemniscal Pathway
Spinothalamic TractSpinothalamic Tract
Spinoreticular or Spinoreticulothalamic TractSpinoreticular or Spinoreticulothalamic Tract
Spinocerebellar TractSpinocerebellar Tract Spinomedullothalamic TractSpinomedullothalamic Tract
Cervicothalamic or Spinocervicothalamic Tract Cervicothalamic or Spinocervicothalamic Tract
Spino-olivary TractSpino-olivary Tract
Spinotectal TractSpinotectal Tract
Spinal Cord TractsSpinal Cord Tracts Spinal Cord TractsSpinal Cord Tracts
Posterior White Column -Posterior White Column -Medial Lemniscal PathwayMedial Lemniscal PathwayPosterior White Column -Posterior White Column -
Medial Lemniscal PathwayMedial Lemniscal Pathway
medial lemniscusmedial lemniscus
lemniscal decussationlemniscal decussation
internal arcuate fiberinternal arcuate fiber
posterior white columnposterior white column
posterior rootposterior root
- - ipsilateralipsilateral loss of discriminative touchloss of discriminative touch sensation and conscious proprioceptionsensation and conscious proprioception belowbelow the level of lesionthe level of lesion
Spinothalamic TractSpinothalamic TractSpinothalamic TractSpinothalamic Tract
spinothalamicspinothalamictracttract
anterior whiteanterior whitecommissurecommissure
posterior rootposterior root
decussationdecussation
- - contralateralcontralateral loss of pain and temperature loss of pain and temperature sensation sensation below below the level of lesionthe level of lesion
Lateral pathway
-Voluntary movement of distal muscles
-Direct cortical control
Ventromedial pathway
-Pose and antigravitational movements
-Indirect cortical (stem) control
Descending tracts
- - ipsilateralipsilateral UMN syndrome UMN syndrome
atat the level of lesion the level of lesion
Corticospinal TractCorticospinal TractCorticospinal TractCorticospinal Tract
Corona Radiata Corona Radiata
lnternal Capsule, Posterior Limblnternal Capsule, Posterior Limb
Crus Cerebri, Middle PortionCrus Cerebri, Middle Portion
Longitudinal Pontine FiberLongitudinal Pontine Fiber
Pyramid Pyramid
Pyramidal DecussationPyramidal Decussation
Corticospinal Tract Corticospinal Tract
- Lateral and Anterior- Lateral and Anterior
CR
IC
LPF
Pyr
PD LCST
ACST
ventromedial pathway
dorolateral pathway
DescendingDescendingTractsTractsfromfromBrain StemBrain Stem
Spinal Cord Spinal Cord TractsTracts
Spinal Cord Spinal Cord TractsTracts
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
Spinal Nerves
• Each connects to the spinal cord by 2 roots – dorsal and ventral.
• Each root forms from a series of rootlets that attach along the whole length of the spinal cord segment.
• Ventral roots are motor while dorsal roots are sensory.
Spinal Nerves• The 2 roots join to form a
spinal nerve prior to exiting the vertebral column.
• Roots are short and horizontal in the cervical and thoracic regions while they are longer and more horizontal in the sacral and lumbar regions.
• After emerging from its intervertebral foramen, a spinal nerve divides into
• dorsal ramus,
• ventral ramus, and
• meningeal branch that recurs to supply the meninges and associated blood vessels.
• Each ramus is mixed.
• Joined to the base of the ventral rami of spinal nerves in the thoracic region are the rami communicantes. These are sympathetic fibers that we’ll deal with shortly.
• Dorsal rami supply the posterior body trunk whereas the thicker ventral rami supply the rest of the body trunk and the limbs.
Reflex Arcs
• A reflex is a rapid, predictable motor response to a stimulus. Unlearned and involuntary.
• Example?
• Components of a reflex arc:– Receptor site of stimulus
– Sensory neuron transmits afferent info to CNS
– Integration center 1 or more interneurons
– Motor neuron transmits efferent signals to effector
– Effector muscle or gland
Reflexes• Reflexes involving skeletal muscles and somatic motor neurons are
somatic.
• Reflexes controlled by autonomic neurons are autonomic.
• Spinal reflexes are integrated w/i the spinal cord while cranial reflexes are integrated in the brain.
• Reflexes may be inborn or learned.
• Reflexes may be monosynaptic or polysynaptic.– Difference?
Spinal Cord SyndromeSpinal Cord Syndrome Spinal Cord SyndromeSpinal Cord Syndrome
Predominantly Motor SyndromesPredominantly Motor Syndromes
• Poliomyelitis (Infantile Paralysis)Poliomyelitis (Infantile Paralysis) - viral infection of lower motor neuron- viral infection of lower motor neuron
- LMN syndrome at the level of lesion- LMN syndrome at the level of lesion
• Amyotrophic Lateral Sclerosis (ALS)Amyotrophic Lateral Sclerosis (ALS) - combined LMN and UMN lesion- combined LMN and UMN lesion
- LMN syndrome at the level of lesion- LMN syndrome at the level of lesion
- UMN syndrome below the level of lesion- UMN syndrome below the level of lesion
- Lou Gehrig’s disease in USA- Lou Gehrig’s disease in USA
Spinal Cord SyndromeSpinal Cord Syndrome Spinal Cord SyndromeSpinal Cord Syndrome
Amyotrophic Lateral SclerosisAmyotrophic Lateral Sclerosis Amyotrophic Lateral SclerosisAmyotrophic Lateral Sclerosis
1. corticospinal tract
2. lower motor neuron (LMN)
Spinal CordSpinal CordSyndromeSyndrome
AmyotrophicAmyotrophicLateral SclerosisLateral Sclerosis
(ALS)(ALS)
Lou Gherig’sLou Gherig’sDiseaseDisease
Spinal CordSpinal CordSyndromeSyndrome
AmyotrophicAmyotrophicLateral SclerosisLateral Sclerosis
(ALS)(ALS)
Lou Gherig’sLou Gherig’sDiseaseDisease Stephen Haking (1946- )Stephen Haking (1946- )
British Physicist, A Brif History of Time
Spinal Cord SyndromeSpinal Cord Syndrome Spinal Cord SyndromeSpinal Cord Syndrome
Brown-Sequard syndromeBrown-Sequard syndrome (spinal cord hemisection)(spinal cord hemisection) Major SymptomsMajor Symptoms
1. ipsilateral 1. ipsilateral UMN syndromeUMN syndrome below below the level of lesionthe level of lesion
2. ipsilateral 2. ipsilateral LMN syndrome LMN syndrome at at the level of lesionthe level of lesion
3. ipsilateral loss of 3. ipsilateral loss of discriminative touch sensation discriminative touch sensation and and
conscious conscious proprioceptionproprioception belowbelow the level of lesion the level of lesion
(posterior white column lesion)(posterior white column lesion)
4. 4. contralateralcontralateral loss of loss of pain and temperature pain and temperature sensationsensation belowbelow the level of lesion the level of lesion (spinothalamic tract lesion) (spinothalamic tract lesion)
Spinal Cord SyndromeSpinal Cord Syndrome Spinal Cord SyndromeSpinal Cord Syndrome
Brown-Sequard Syndrome (Spinal Cord Hemisection)Brown-Sequard Syndrome (Spinal Cord Hemisection) Brown-Sequard Syndrome (Spinal Cord Hemisection)Brown-Sequard Syndrome (Spinal Cord Hemisection)
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