Functional anatomy and Physiological significance of Spinal Cord

1. SPINAL CORD
Dr. Aniket A.
Shilwant
Assistant Professor
Dept. of Kriya Sharir
GJP-IASR
CVM University

2. TABLE OF CONTENTS
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Introduction to Spinal cord
Segments of Spinal cord
Histology of Spinal cord
Tracts
Ascending tracts
Descending tracts
 Pyramidal tracts
 Extra pyramidal tracts

3. INTRODUCTION TO SPINAL CORD
 Situation –
• Suspended in Vertebral column
• Continuous extension of Medulla O
 Extent – L1 / L2
 Coverings –
• Meninges – Dura, Arachnoid, Pia mater
 Length – 45cm
 Shape – Cylindrical
Dr. Aniket A. Shilwant, GJPIASR
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4. INTRODUCTION TO SPINAL CORD
 Enlargements –
• Cervical & Lumbar Enlargements – Innervates UL & LL
• Cervical Enlargements – C4 – T1
• Lumbar Enlargements – T9 – T12
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5. INTRODUCTION TO SPINAL CORD
 Conus Medullaris
 Immediate narrowing of SC below lumbar enlargement
 Cone shaped termination – Conus medullaris
 Ends between L1 & L2
 Filum Terminale
 Non nervous, fibrous tissue attaching Coccyx
 Pia mater
 Cauda equina
 Spinal cord – Total 31 segments each giving rise to pair of
Spinal nerves
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6. SEGMENTS OF SPINAL CORD
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 CERVICAL SEGMENT – CERVICAL SPINAL NERVES – 8
 THORACIC SEGMENT – THORACIC SPINAL NERVES – 12
 LUMBAR SEGMENT – LUMBAR SPINAL NERVES – 5
 SACCRAL SEGMENT – SACCRAL SPINAL NERVES – 5
 COCCXYGEAL SEGMENT – COCCXYGEAL SPINAL NERVE – 1

7. HISTOLOGY OF SPINAL CORD
Grey mater
Nerve cell bodies, Dendrites, Neuroglia
& Unmyelinated Axons
White mater
Myelinated Axons with Neuroglia
Tract / Fasciculus
Bundles of fibers
Horns
2D appearance
Grey mater area
Columns
3D appearance
Grey mater
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9. TRACTS
Classification of Tracts –
On basis of length
 Short tracts – Association and Commissural fibers
 Long tracts – Projection fibers
On basis of nature (direction)
 Ascending tracts – Afferent
 Descending tracts – Efferent
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10. TRACTS
Neural pathway –
 First order neurons
 Second order neurons
 Third order neurons
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12. ASCENDING TRACTS
Anterior Spino-Thalamic Tract
Location:- Anterior Column
Origin:- Posterior Grey Horn cell
Termination:- Thalamus – Cerebral Cortex
Function:- Crude Touch, Pressure
Lateral Spino-Thalamic Tract
Location:- Lateral Column
Origin:- Posterior Grey Horn cell
Termination:- Thalamus – Cerebral Cortex
Function:- Pain and Temperature
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13. ASCENDING TRACTS
Ventral Spino-Cerebellar Tract
Location:- Lateral Column
Origin:- Posterior Grey Horn cell
Termination:- Cerebellum – Cerebral Cortex
Function:- Subconscious kinesthetic sensation
Dorsal Spino-Cerebellar Tract
Location:- Lateral Column
Origin:- Posterior Grey Horn cell
Termination:- Cerebellum – Cerebral Cortex
Function:- Subconscious kinesthetic sensation
Dr. Aniket A. Shilwant, GJPIASR
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14. ASCENDING TRACTS
Spino-Tectal Tract
Location:- Lateral Column
Origin:- Posterior Grey Horn cell
Termination:- Superior colliculus in midbrain
Function:- Spino visual reflex
Spino Reticular Tract
Location:- Lateral Column
Origin:- Posterior Grey Horn cell
Termination:- Reticular formation of brain stem
Function:- Consciousness and awareness
Dr. Aniket A. Shilwant, GJPIASR
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15. ASCENDING TRACTS
Spino-Olivary Tract
Location:- Lateral Column
Origin:- Posterior Grey Horn cell
Termination:- Olivary nucleus in Medulla
Function:- Proprioception
Spino-vestibular tract
Location:- Lateral Column
Origin:- Posterior Grey Horn cell
Termination:- Lateral vestibular nucleus in Medulla
Function:- Proprioception
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16. ASCENDING TRACTS
Fasiculus gracilis
Location:- Posterior Column
Origin:- Posterior Grey Horn cell
Termination:- Nucleus Gracilis in Medulla
Function:- Tactile Sensation, Localization,
Discrimination, Vibratory sensation, Stereognosis
Fasiculus cuneatus
Location:- Posterior Column
Origin:- Posterior Grey Horn cell
Termination:- Nucleus Cuneatus in Medulla
Function:- Tactile Sensation, Localization, Discrimination, Vibratory sensation,
Stereognosis
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NAME OF TRACT ORIGIN PATHWAY TERMINATIO FUNCTION EFFECT OF LESION
ANT.
SPINOTHALAMIC
POSTERIOR
NERVE ROOT
GANGLION
CROSSED
VENTRAL
POSTERO –
LATERAL
NUCLEUS OF
THALAMUS
CRUDE TOUCH
PRESSURE
LOSS OF CRUDE
TOUCH & PRESSURE
SENSATION
LAT.
SPINOTHALAMIC
PAIN TEMPERATURE
ANAESTHESIA
THERMO-
ANAESTHESIA
ANT. SPINO
CEREBELLAR
CROSSED
ANTERIOR
LOBE OF
CEREBELLUM
PROPRIOCEPTION
SUBCONSIOUS
KINESTHETIC
SENSATIONS
LOSS OF
PROPRIOCEPTION
SUBCONSIOUS
KINESTHETIC
SENSATIONS
POST. SPINO
CEREBELLAR
UNCROSSED

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NAME OF
TRACT
ORIGIN PATHWAY TERMINATION FUNCTION EFFECT OF LESION
SPINO
OLIVARY
POSTERIOR
NERVE ROOT
GANGLION
UNCROSSED
OLIVARY
NUCLEUS –
MEDULLA
PROPRIOCEPTION
LOSS OF
PROPRIOCEPTION
SPINO
RETICULAR
BOTH
RETICULAR
FORMATION –
MEDULLA &
PONS
CONSCIOUSNESS
& AWARENESS
ANOSGNOSIA
SPINO
TECTAL
CROSSED
SUPERIOR
COLLICULLI
SPINO VISUAL
REFLEX
LOSS OF SPINO
VISUAL RESPONSE
SPINO
VESTIBULAR
BOTH
VESTIBULAR
NUCLEI –
MEDULLA
PROPRIOCEPTION
LOSS OF
PROPRIOCEPTION
FASICULUS
DORSO-
LATERALIS
CROSSED
POSTERO-
VENTRAL
NUCLEUS OF
THALAMUS
PAIN &
TEMPERATURE
ANAESTHESIA
THERMO-
ANAESTHESIA

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NAME OF
TRACT
ORIGIN PATHWAY TERMINATION FUNCTION EFFECT OF LESION
FASICULUS
CUNEATUS POSTERIOR
NERVE
ROOT
GANGLION
UNCROSSED
NUCLEUS
CUNEATUS
TACTILE –
SENSATION
LOCALIZATION
DISCRIMINATION
STEREOGNOSIS
LOSS OF - TACTILE –
SENSATION
LOCALIZATION
DISCRIMINATION
ASTEREOGNOSIS
FASICULUS
GRACILIS
NUCLEUS
GRACILIS

20. DESCENDING TRACTS
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21. Dr. Aniket A. Shilwant, GJPIASR
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22. PYRAMIDAL TRACTS
Anterior Cortico-Spinal tract
Location:- Anterior (Ventral) Column
Origin:- Primary, Pre motor & Somatosensory area.
Termination:- Anterior (Ventral) grey horn
Function:- Motor impulses for precise skeletal movements.
Maintain muscle tone.
Lateral Cortico-Spinal tract
Location:- Lateral Column
Origin:- Primary, Pre motor & Somatosensory area
Termination:- Anterior (Ventral) grey horn
Function:- Motor impulses for skeletal muscles to provide precise, accurate & discrete
movements.
Dr. Aniket A. Shilwant, GJPIASR
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23. EXTRA-PYRAMIDAL TRACTS
Anterior Vestibulo-Spinal tract
Location:- Anterior Column
Origin:- Medial Vestibular Nucleus
Termination:- Anterior Grey horn cell
Function:- Muscle tone, Posture, Equilibrium in response to
gravity, linear and angular motion
Lateral Vestibulo-Spinal Tract
Location:- Lateral Column
Origin:- Lateral Vestibular Nucleus
Termination:- Anterior grey horn cell
Function:- Muscle tone, Posture, Equilibrium in response to gravity, linear and angular motion.
Dr. Aniket A. Shilwant, GJPIASR
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24. EXTRA-PYRAMIDAL TRACTS
Reticulo-Spinal Tract
Location:- Anterior Column
Origin:- Reticular formation of Pons (Uncrossed) & Medulla (Both crossed & uncrossed)
Termination:- Anterior Grey horn cell
Function:-
Functions Pontine Medullary
Respiration Expiration Inspiration
Blood vessels Vasoconstriction Vasodilation
Muscle tone Facilitation Inhibition
Muscle movements Facilitation Inhibition
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25. Dr. Aniket A. Shilwant, GJPIASR
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Rubro-Spinal Tract
Location:- Lateral Column
Origin:- Red Nucleus, crosses on opposite side
Termination:- Aterior Grey horn cell
Function:- Concerned with muscle tone & posture
Olivo-Spinal Tract
Location:- Lateral Column
Origin:- Olivary Nucleus of Medulla
Termination:- Anterior Grey Horn cell
Function:- Controls reflex movements arising form proprioreceptors
EXTRA-PYRAMIDAL TRACTS

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EXTRA-PYRAMIDAL TRACTS
Tecto-Spinal Tract
Location:- Anterior Column
Origin:- Tectum (Midbrain) from one side and
crosses on other side.
Termination:- Anterior grey horn cell
Function:- Movements of head in response to
Visual and Auditory stimuli.

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NAME OF
TRACT
ORIGIN PATHWAY TERMINATION FUNCTION EFFECT OF LESION
ANT.
CORTICO
SPINAL
PRIMARY
PRE MOTO
AREA
UNCROSSED
ANTERIOR
NERVE ROOT
GANGLION
VOLUNTARY
MOTOR ACTIVITIES
LOSS OF VOLUNTARY
ACTIVITIES
SPASTICITY,
HYPERTONIA
EXAGGERATED, BRISK
REFLEXES
HEMIPARESIS
HEMI & OR QUADRI
PLEGIA
LAT.
CORTICO
SPINAL
PRIMARY
PRE MOTO
AREA
CROSSED
ANT.
VESTIBULO
SPINAL
MEDIAL
VESTIBULAR
NUCLEUS
UNCROSSED
MUSCLE TONE,
POSTURE
POSITION OF
HEAD & BODY
W.R.T GRAVITY &
ACCELERATION
DIFFICULTY IN
MOVEMENTS OF HEAD
& BODY W.R.T GRAVITY
& ACCELERATION
LAT.
VESTRIBULO
SPINAL
LATERAL
VESTIBULAR
NUCLEUS

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NAME OF
TRACT
ORIGIN PATHWAY TERMINATION FUNCTION EFFECT OF LESION
TECTO
SPINAL
SUPERIOR
COLLICULI
CROSSED
ANTERIOR
NERVE ROOT
GANGLION
SPINO VISUAL
REFLEX
LOSS OF SPINO VISUAL
REFLEX
OLIVO
SPINAL
OLIVARY
NUCLEUS –
MEDULLA
PROPRIOCEPTION
LOSS OF
PROPRIOCEPTION
RUBRO
SPINAL
RED
NUCLEUS –
MB
CROSSED
FACILITATES
MUSCLE TONE
ALTERS MUSCLE TONE

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NAME OF
TRACT
ORIGIN PATHWAY
TERMINATIO
N
FUNCTION EFFECT OF LESION
RETICULO
SPINAL
RETICULAR
FORMATION
– PONS &
MEDULLA
CROSSED
ANTERIOR
NERVE ROOT
GANGLION
VOLUNTARY MOTOR
ACTIVITIES, MUSCLE
TONE, REG. OF TONE
OF BLOOD VESSELS,
RESPIRATORY
CONTROL
DISTURBANCES IN
RESPIRATION, BLOOD
PRESSURE, MUSCLE
TONE & MOVEMENTS
OF BODY
MEDIAL
LONGITUDNAL
FASICULUS
SUPERIOR
COLICULI,
RETICULAR
FORMATION,
VESTIBULAR
NUCLEI
UNCROSSED
ANTERIOR
NERVE ROOT
GANGLION
REFLEX OCULAR
MOVEMENTS WITH
HEAD & NECK
UNABLE TO PERFORM
REFLEX OCULAR
MOVEMENT

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31. Thank You All !!!
Dr. Aniket A. Shilwant
Assistant Professor
Sharir Kriya Dept.
GJP-IASR, CVM University
Email –
ayuraniket18@gmail.com
http://ayugjac.edu.in/Staff_CV.aspx?dl=dn3Mja19480dn3Mja19
http://scholar.google.co.in/citations?user=636K2sMAAAAJ&hl=en
https://www.researchgate.net/profile/Aniket_Shilwant