Spinal Cord Flashcards

1
Q

Paralysis following spinal cord injury

A
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2
Q

Where does the spinal cord begin

What is it continuous with at its origin

A

Begins at foramen magnum

Continuous with medulla

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3
Q

Diameter and length of the spinal cord

A

Diameter = 1-1.5cm

Length = 45cm

Hence occupies upper 2/3rd of vertebral canal of vertebral column

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4
Q

Where does the spinal cord terminate in

  1. Adults
  2. Children

Why does the spinal cord terminate before the vertebral column

A
  1. L1-L2 in adults
  2. Near L3 in young child

Rate of growth of bone (vertebral column) tissue is faster than the rate of growth of nerve tissue

Hence lumbar cistern below termination point

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5
Q

How the 3 meningeal layers transfer to spinal cord

A
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6
Q

What anchors the spinal cord in its position

A

Denticulate ligament

A continuation of pia mater

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7
Q

Name and indentify where there are enlargements in the spinal cord

A
  • Cervical enlargement - origin to brachial plexus (C3-T2)
  • Lumbar enlargement - origin to lumbosacral plexus (L1-S3)
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8
Q

Name the most inferior structure of the spinal cord

A

Spinal cord tapers off into CONUS MEDULLARIS

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9
Q

What is the cauda equina

A

Extension of bundle of nerve roots beyond the cord

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10
Q

What is the filum terminale

A

A prolongation of pia mater

Descends from conus medullaris to attach to coccyx (anchor)

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11
Q

Dissections of conus medullaris, cauda equina, meningeal layers and filum terminale

A
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12
Q

What opening do nerves pass through

A

Intervertebral foramina

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13
Q

Transverse section of spinal cord

A
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14
Q

How to distinguish the dorsal (sensory) root from the ventral (motor) root

A

Sensory ganglia - swelling

* Dorsal root ganglion

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15
Q

Dorsal/posterior roots are _______

A

Sensory

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16
Q

Ventral/anterior roots are ________

A

Motor

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17
Q

How is each root attached to the cord

A

By a series of rootlets

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18
Q

What does the spinal nerve branch into

A

Anterior/ventral ramus

Posterior/dorsal ramus

Series of smaller branches

19
Q

Transverse process of spinal cord & spinal nerve branches

A
20
Q

What is the dermatomal map

A

Each spinal nerve carries sensory information for a part of the body surface

Sensation lost in 1 dermatome only when approx 3 adjacent roots have been injured, hence there is a compensatory effect

21
Q

What do afferent nerve fibres do

A

Bring information to the spinal cord which then travels up to the brain

22
Q

What do efferent nerve fibres do

A

send information from the spinal cord out along nerves

23
Q

Transverse section of spinal cord

A

Note - grey matter is at the centre, white matter at the surface edge

24
Q

What lines the central canal

A

Ependymal cells

25
Q

What happens if the fluid in the 4th ventricle does not drain down to the central canal

A

It goes to the 3 apertures in the roof of the 4th ventricle

26
Q

Divisions of grey matter

A

Dorsal/posterior column

Ventral/anterior column

Lateral column (intermediate zone)

Rexed’s laminae - 10 zones

27
Q

Where is true lamination confined to

A

Dorsal horn

28
Q

What is the substantia gelatinosa in the dorsal grey column

A

Apex of dorsal grey column throughout cord length

Receives afferents related to pain, temperature, touch from dorsal root

29
Q

What is the nucleus proprius in the dorsal grey column

A

Ventral to substantia gelatinosa throughout the length

Receives fibres from dorsal white columns

Senses of position, movement (proprioception)

30
Q

What is the nucleus dorsalis/Clarke’s column in the dorsal grey column

A

Base of dorsal grey column

C8 - L3/4 segments

Proprioceptive signals - cells give rise to posterior spinocerebellar tract

31
Q

What do the nerve cell groups in ventral gray columns do

A

Cell columns of lower motor neurons in ventral grey matter supply groups of muscles with similar functions

32
Q

Difference between monosynaptic and polysynaptic

A
33
Q

What is the amount of grey matter present proportional to

A

The amount of muscle innervated at that level

34
Q

Define the 3 divisions of white matter

A
  • Anterior/ventral funiculus - between anterior median fissure and anterolateral sulcus
  • Lateral funiculus - between anterolateral sulcus and posterolateral sulcus
  • Posterior/dorsal funiculus - between posterolateral sulcus and dorsal median sulcus
35
Q

What do the ascending tracts of white matter carry impulses from

A

Pain

Tactile, thermal, muscle and joint receptors

=> exteroeceptive and proprioceptive info

36
Q

What are the descending tracts of white matter involved in

Define their path

A

Descend down from cerebral cortex and brain

Involved in control of movement, posture, muscle tone

37
Q

Define intersegmental tracts

A

Fibres carry info from 1 segment to another

Important intersegmental spinal reflexes

38
Q

What are the principle fibre tracts of the spinal cord

A
39
Q

Name the 3 arteries that supply the spinal cord

A

Anterior medial spinal artery

2 x smaller posterior spinal arteries

40
Q

Where is the anterior median spinal artery located

How much of the blood supply does it constitute

A

Located along the anterior midline of the cord

Supplies most (75%) of the arterial blood supply to spinal cord

41
Q

Where are the smaller posterior spinal arteries located

How much of the blood supply do they constitute

A

Lie on each side of the cord posteriorly

Supplies only 25% of the arterial blood supply to posterior region of spinal cord

42
Q

Origin of the posterior spinal arteries

A

Directly from vertebral spinal arteries or INDIRECTLY from posterior inferior cerebellar arteries

43
Q

Origin of anterior spinal artery

A

Formed by union of the 2 branches of the vertebral arteries

44
Q

Veins of the spinal cord

A

Drain into 6 longitudinal channels

  • Anterior spinal v.
  • Posterior spinal v.
  • Anterolateral v.
  • Posterolateral v.

=> into anterior and posterior radicular veins

  • Radicular veins drain into internal vertebral venous plexus