Spinal Cord Pre-lab Lecture

7/25/2019 Spinal Cord Pre-lab Lecture

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Bassett Collection of Stereoscopic Ima

Lab 2: Spinal Cord

Cordelia Erickson-Davis

[email protected]

January 21 2016


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Case studyA more detailed neurological exam revealed:

Ipsilateral to the lesion:

Contralateral to the lesion:

Loss of motor function

joint position

vibration sense below thelesion

fine touch

Loss of pain sensation

temperature and

crude touch below the level of the lesion.


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Case study:


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Bassett Collection of Stereoscopic Ima

Functions of the Spinal Cord

1. Conduit between brain andperiphery

2. Final common pathway for motor

output3. Basic sensorimotor processing


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Bassett Collection of Stereoscopic Images of Human Anatomy.

Overvie

1. External an

2.

Internal an3. Circuitry/P

4.

Lesions &


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Overvie

1.

External an

2. Internal ana

3.

Circuitry/Pa4.

Lesions & D


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The Spinal Cord is

SMALL

42-45 cm


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31 pairs of

spinal ne

Brachial

plexus

30,000 miles of periphera

some neuron


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The Spinal Cord is Divided Into Functional Units

Vertebral body

Spinal

nerve

Pedicle

Spinous process

Spinal cord

A

P

8 cervic

12 thorac

5 lumba

5 sacr

1 coccygeNolte, J. & Angevine Jr., JB. (2007) The Human Brain in Photographs and D


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Each segment specifies dermatome or myoto

Thieme Atlas of Anatomy: Head and Neuroanatomy. (2010) Schuenke, Schulte & Schumacher.


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Review: The Cranial Meninges


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pia mater

arachnoid

dura mater

Spinal Meninges are Continuous with the Cranial M


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VERTEBRA

..BUT Spinal Meninges are Different than Cranial M

spinal cord

pia mater

arachnoid

dura mater

fat/venous plexus

only a single layer of dura(continuous with meningeal layer)


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Venous plexus is within the epidura

Upper thoracic spLumbar spinal cordBassett Collection of Ste

venous

plexus

Thieme Atlas of Anatomy: Head and Neuroanatomy. (2010) Schuenke, Schulte & Schumacher.


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C4

C3

C5

C6

C7

Hendelman, WJ.Atlas of Functional Neuroanatomy, 2nd

A look inside the

pial sp

d

arach


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A closer look at the infe

conus

medullaris

cauda

equina

cauda equina



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L5 L4 L3

L5

L4

L3

L2

MRI from mr-tip.com

conus

medullaris

lumbar

cistern

Lumbar pu

Video at http://www.nejm.org/doi/full/

L1

L2

L3

L4

L5

S1S2


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C4

C3

C5

C6

C7

Pial specializations stabilize the spina

denticulate

ligaments

caud

equin

fi

Hendelman, WJ.Atlas of Functional Neuroanatomy, 2ndedition (2007). CRC Press.


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Lets Synthesize All This Anatomy In Situ

meninge

(dura mate

spinal venous

plexus

denticulateligament

meninges

(arachnoid layer)

Bassett Collection of Ste

M i t th A i


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C4

C3

C5

C6

C7

Moving on to the

vasculature

d

arachn

Anterio

anterior spina

denticul



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Review: The dorso-ventral axDorsal

Ventralbelly

Dorsbac

Rostral

Caudal

Anterior

Ceph

V l t S l i th S i l C d


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vertebral arteries

anterior spinal artery

Vasculature Supplying the Spinal Cord



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anterior 2/3 of spinal cord


posterior spinal arteries

Vasculature Supplying the Spinal Cordposterior spinal art

Thieme Atlas of Anatomy: Head and Neuroanatomy. (201



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radicular arteries

Skandalakis JE, Colborn GL, Weidman TA et al. Skandalaskis Surgical Anatomy (2009). McGraw-Hill Companies.

Vasculature Supplying the Spinal Cord


anterior 2/3 of spinal cord

posterior spinal art

Lets Synthesize All This Anatomy In Situ


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Let s Synthesize All This Anatomy In Situ

meninge

(dura mate

spinal venous

plexus

denticulateligament

meninges

(arachnoid layer)

Bassett Collection of Ste


vertebral arte

radicular artery


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Overvie

1.

External an

2. Internal ana

3.

Circuitry/Pa

4.

Lesions & D


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Lets cut into t

cervical

thoracic

lumbar

sacral

Dorsal Ventral

Your Typical Spinal Cord Section Looks Like


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Your Typical Spinal Cord Section Looks Like

white matter

g

The Human Brain in Photographs and Diagrams. Nolte J & Angevine Jr. JB Brain Atlas, 3rd edition (2007).

th t hit tt i t hit


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white matter

gr

The Human Brain in Photographs and Diagrams. Nolte J & Angevine Jr. JB Brain Atlas, 3rd edition (2007).

that white matter is so not white

Thats Because Weve Stained the M


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That s Because We ve Stained the M

white

matter

gray

matter

Thats Because Weve Stained the M


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Luxol Blue/Weil-staine

That s Because We ve Stained the M

Electron micrograph of myelin

Compare/Contrast: Brain to Spin


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white matter

g

Compare/Contrast: Brain to Spin

gray matter

white matter

Lets orient ourselves!D posterolateral sulci


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dorsal/posterior

ventral/anterior

anterior median fissure

dorsal columns

V

anterior sp

posterolateral sulci

Lets Synthesize All This Anatomy In Sit


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Let s Synthesize All This Anatomy In Sit

meninge(dura mat

spinal venous

plexus

denticulateligament

meninges

(arachnoid layer)

Bassett Collection of S


vertebral arte

dorsal columnsposterolateral

sulci

dorsal surface, cervical spinal cord.

Basic Functional Organization of the SpinD


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Basic FunctionalOrganization of the Spin

SEV

Sensory dorsal, motor D


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dorsal root ganglion

y ,V

ventral root

dorsal root

dorsal root

ganglion

spinal nerve spinal motor

Where is the boundary betw

D


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Spinalcord

yV

oligodendrocytesastrocytes

Schwann cells

dorsal or ventral rootlet

RedlichObersteiner zone

The spinal cord is NOT uniform


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T phow do we figure out where we ar

Tips for Success:1. Find a landmark 2. Orient yourself (which way is N

3.Walk around, explore the local neighborhood

How to identify spinal cord segments


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cervical

thoracic

lumbar

sacral

1. Use what weve already learned to orient thesections

-

Posterolateral sulci- Anterior median fissure

2.

As you ascend the spinal cord, sections tend tohave increased white matter. Why?

3. Spinal cord is larger at the cervical and lumbar

regions-

Gray to white matter ratio

-

Cervical and lumbar enlargements

Keep these tips in mind for next week


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p pbrainstem!

Brainstem section

Spinal Cord Gray Matter


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p ydorsal

(SENSORY)

ventral

(MOTOR)

marginal zon

nuc

ClaVIIVII

VIIVII

IntermeCell C

substa

gelatin

Review: the Autonomic Nervous System


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HOMEOSTASIS

Sympathetic

Nervous System

fight or flight

The balance between sympa

parasympathetic nervous systems

!blood pressure

!pupil size, focusing the lenthe eyelid

!glandular secretion

!urogenital reflexes: bladder

erection


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IML = preganglionic neurons

of the sympathetic nervous

system

VIIVII

Intermediolateral(IML) Cell Column

(T1-L2)

pre-ganglionic

neuronsin the

interomediolateral

column (IML)

T1-L2

neurotransmitter:

Ach

neurons from

sympathetic ganglia

to effector organs

Superior Cerv

Ganglion

Pa

Sy

Superior Mesen

Ganglion

Inferior MeseGanglion

neurotransmitter:

norepinephrine

Spinal Cord Gray Matter


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motor neurons

dorsal(SENSORY)

ventral

(MOTOR)

marginal zon

nuc

ClaVIIVII

VIIVII

IntermeCell C

substa

gelatin

VIIIVIIIIX

IX IX IXIX

motor inter

X

central gray

Nissl

A closer look at spinal motor neur

D


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Sukiasyan et al., Neuroscience, 2009

medialmotor neurons m

Flexors

Extensors

Axial

muscles

V

Overvie


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Overvie

1.

External an

2. Internal an

3.

Circuitry/P

4.

Lesions &

Important questions to consider


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p qpathways

1.

What information (modality) is carried?2. Where does it start and end?

3. Where does it decussate (cross midline)?

4.

What is the 1st, 2nd, nthorder neuron?

Spinal Cord White MatterD


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lateral ct

fasciculus gracilus

fasciculus cun

spin

antero

system

V

DORSAL COL

Spinal Cord White MatterD


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fasciculus gracilus

fasciculus cun

spin

antero

system

V

DORSAL COLAscending pathwaysDorsal column/Medial

lemniscus

Anterolateral system

Dorsal spinocerebellar

Descending pathway

Lateral corticospinal tract

lateral ct

Dorsal Column/Medial Lemniscus Pathway


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What information does the pathway carry?The BIG FOUR

Fine Touch

Proprioception

Stereognosis

Vibration Sense

What neurons comprise this circuit?1. Peripheral tissue to nucleus gracilis/cuneatus

2. Nucleus gracilis/cuneatus to VPL thalamus

3. VPL thalamus to somatosensory cortex

nucleusgracilis

Dorsal Column/Medial Lemniscus Pathway


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What information does the pathway carry?The BIG FOUR

Fine Touch

Proprioception

Stereognosis

Vibration Sense

What neurons comprise this circuit?1. Peripheral tissue to nucleus gracilis/cuneatus

2. Nucleus gracilis/cuneatus to VPL thalamus


nucleusgracilis

DC/ML Inputs are Topographically OrganizeD


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from

legs

cervical

thoracic

lumbar

from

trunk

from

armsV

Anterior lateral system:Spinothalamic & Spinoreticular T


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What information does the pathway carry?The little 3

Pain

Temperature

Crude Touch

What neurons comprise this circuit?

1. Peripheral tissue to marginal zone/substantiagelatinosa

2. Marginal zone/substantia gelatinosa to VPL

thalamus (2/3) or reticular formation (1/3)


Dorsal Spinocerebellar Tract


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FROM LEGS1. Peripheral tissue to Clarkes column

2. Clarkes column to cerebellum viainferior cerebellar peduncle

FROM ARMS1. Peripheral tissue to accessory cuneate

nucleus

2 Accessory cuneate nucleus to cerebellum

What information does the pathway carry?

Unconscious proprioception

accessorycuneate n.

Clarkescolumn

Corticospinal Tract


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What information does the pathway carry?

Voluntary movement


1. Neurons in motor and premotor cortex to VIII

interneurons (99%) and motor neurons (1%)

2. Motor neurons to muscle fibers

Upper

MotorNeuron


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Overvie

1.

External an

2. Internal ana

3.

Circuitry/Pa

4.

Lesions & D

Localizing neurological causes for muscle w


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UPPER NEURON DEFICIT LOWER NEURON D

No significant muscle atrophy Significant Atrop

Spastic paralysis (Hypertonia) Flaccid paralysis (Hy

Fasciculations and fibrillations not

present

Fasciculations and fib

present

Hyperreflexia Hyporeflexia

>Babinski reflex may be present > Babinski reflex not

Case Study:Brown-Squard Syndrome (a transverse


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Brainstem

SpinalCord

hemi-section of the spinal cord)

Big 4

Little 3

UnconsciousProprioception

Voluntary MovementWhat functi

below the lIpsilat

- BIG 4

- unconscious

- voluntary moContral

- Little 3

Overv


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1. External an

2.

Internal an

3.

Circuitry/P

4.

Lesions &

Some Administrative Details.


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Lab Rooms:

Go to your lab room f

Review Sessions:

The usual: Wed, 7PM M

Lab Manual:Pre-read it, yo

TEA TIME

Cookies before lab,Tea and cookies after

Canvas Discussion Board

Burning questions? Let us help

Brain Day!Sign-up:https://docs.google.com/spreadsheets/d/18AHwwLpSmRJv4Dwzs8u9yMFCvVHCcMMOvMiWV3RW


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Stay tuned for next week!


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Supplementary Slides

Position of the Spinal Cord Relative to the Ver


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vert

bo

spinal cordspinal nerve

intervertebral

foramenspinous

process

intravertebral

disc

Differential growth of the spinal cord and vertebral column sespinal cord segments from their associated skeletal eleme

(progressively greater mismatch at caudal levels)


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(progressively greater mismatch at caudal levels)

Spinal Cord

SegmentVertebral Body

C8 C6-C7

T6 T5

T12 T10

L3 T11

S1 T12

Vitamin B12 Deficiency


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From Neurology Board Review:

Fig. 20-6. Pathologic features of subacute combined degeneration of vitamin B1A, Note the symmetric loss of myelin staining predominantly involving the postercolumns (Luxol fast blue stain.)B, Histopathologic features of vacuolar myelopathy: spongy white matter vacuolizposterior and lateral columns. (From Okazaki H, Scheithauer BW. Atlas ofneuropathology. New York: Gower Medical Publishing; 1988, p. 255. By permission of Mayo Foundation.)

Spinal Muscular Atrophy


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From Neurology Board Review:

Fig. 20-3. Diffuse, severe atrophy of the lower extremities in a patient with spinal Overviewa. Clinically heterogenous group of disorders characterized by muscle weakness and atrophy without sensory loss or upper motlower motor neuron syndrome) (Fig. above)b. Pathologically due to degeneration of motor neurons (anterior horn cells) in spinal cord and brainstemc. Most common forms of SMA present in childhood with symmetric proximal (more than distal) limb weakness and atrophy; shoinheritance

Spinal Cord Pre-lab Lecture

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