Spinal Cord Function & Dysfunction Flashcards

1
Q

2 areas of the spinal cord which has enlargement?

A

Cervical (C3-T1)

Lumbar (L1-S3)

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2
Q

Why do these 2 areas of the spinal cord have enlargement?

A

Cervical - extra motor neurones to innervate the upper limbs

Lumbar - extra motor neurones to innervate the lower limbs

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3
Q

Spinal cord segements?

A

31 spinal segments

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4
Q

Which regions make us the pair of spinal nerves?

A
8 - cervical
12 - thoracic
5 - lumbar
5- sacral
1 - coccygeal
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5
Q

How do the nerves leave the vertebral column?

A

Through the intervertebral foramina

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6
Q

Do the nerves come UP or BELOW the vertebrae?

A

C1 - C7 - ABOVE

C8 onwards BELOW (as only have 7 cervical vertebrae so C8 comes out BELOW C7)

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7
Q

Relationship betw. spinal levels and vertebral levels?

A

Spinal cord stop developing early on - so smaller than number of vertebrae

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8
Q

Meningeal coverings of the spinal cord?

A

3 layers of meninges - dura, arachnoid & pia

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9
Q

Where is the CSF located in the spinal cord?

A

Subarachnoid space

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10
Q

Difference in meningeal coverings in cranial and spinal cord?

A

Spinal cord - has unique extradural space (space betw. SC and vertebral column)

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11
Q

What is unique about the extradural space in the SC?

A

Full of venous plexuses & fatty tissue

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12
Q

Clinical relevance of extradural space in SC?

A

Can be used to clinically inject anaesthetic - epidural

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13
Q

Denticulate ligaments?

A

Small protrusions of pia mater that tether the spinal cord

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14
Q

How can you identify cervical vertebrae?

A

Has TWO transverse foramina - to transmit nerves to the brain

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15
Q

At which level does the spinal cord end?

A

At around L2

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16
Q

Filum terminale?

A

An extension of the pia mater that is attached to the coccygeal segments, whose function is to suspend the cord in the CSF (like the denticulate ligaments)

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17
Q

Grey & white matter in spinal cord?

A

Grey matter - cell bodies

White matter - tracts

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18
Q

Dermatome?

A

Area of SKIN innervated by a single pair of nerves

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19
Q

Myotome?

A

Collection of MUSCLES innervated by a single pair of nerves

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20
Q

Anterior/ventral root?

A

Only contains MOTOR fibres

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21
Q

Posterior/dorsal root?

A

Only contains SENSORY fibres

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22
Q

Spinal nerve?

A

When both ROOTS join together (both sensory & motor fibres)

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23
Q

What does the spinal nerve divide into?

A

Dorsal & Ventral ramus

24
Q

Anterior/ventral ramus?

A

MUCH LARGER - goes to everything else

25
Posterior/dorsal ramus?
MUCH SMALLER - branches to muscles & skin of the BACK
26
Difference between roots & ramus?
Roots - either contains sensory OR motor Ramus - contains BOTH types
27
Posterior median sulcus (OneNote)
Divides dorsal surface of SC into two halves
28
Posterolateral sulcus (OneNote)
ENTRY point of the dorsal (sensory) root
29
Anterolateral sulcus (OneNote)
EXIT point of the ventral (motor) root
30
Anterior median fissure (OneNote)
Divides ventral surface of SC into two halves
31
Relationship betw. gray matter & discriminative touch and proprioception?
1. Sensory fibres enter dorsal horn | 2. Travel to dorsal columns W/ synapsing @ ventral horn
32
Relationship betw. gray matter & pain and temperature?
1. Fibres enter dorsal horn 2. May travel up or down column via. posterolateral fasciculus 3. Synpase in nucleus proprius 4. Fibres cross midline in anterior commissure 5. Travel in spinothalamic tract
33
Relationship betw. gray matter & motor neurones?
1. alpha-motor neurones located in ventral horn 2. Exit spinal cord 3. Travel to target muscles Interneuron circuits in ventral horn filter descending motor info.
34
3 main major tracts of SC?
x Spinothalamic x Lateral Corticospinal x Dorsal column
35
What does the spinothalamic tract transfer?
Pain & Temperature!! Contralateral Neurones decussate at
36
At which level does the spinothalamic tract decussate?
At the SAME LEVEL as the entry point of the sensory nerve
37
What does the corticospinal tract transfer?
Main voluntary movement pathway (MOTOR!!!)
38
At which level does the corticospinal tract decussate?
At the level of the MEDULLA
39
Anterior corticospinal tract? (OneNote!)
MOTOR to ipsi & contralateral ventral horn (as can go either way) Towards trunk and head
40
Lateral corticospinal tract? (OneNote!)
MOTOR to ipsilateral ventral horn (either comes from L or R) Towards limbs
41
What does the dorsal column transfer?
Discriminative touch, vibration and proprioception
42
Fasciculus gracilis?
Sensory from ipsilateral lower limb (dorsal column)
43
Fasciculus cuneatus?
Sensory from ipsilateral upper limb (dorsal column)
44
Lateral horn / intermediate column?
Contains neurones that innervates visceral and pelvic organs
45
Which vertebrae contains lateral horn / intermediate column?
Thoracolumbar - site of SN motor neurones Sacral - PSN
46
3 factors affecting severity of spinal lesions?
x Loss of neural tissue x Vertical level x Transverse plane
47
Loss of neural tissue?
Small - if due to trauma More extensive - e.g. metastases or degenerative disease MRI!
48
Vertical level?
The higher the lesion = the greater the disability
49
Transverse level?
Most lesions are not complete - the extent of the damage depends on which part of the spinal cord (particularly white matter) has been injured
50
Where are the major tracts found?
ONENOTE!!!
51
How many stages are their to lateral corticospinal tract injury?
2
52
Stage 1 of injury to lateral corticospinal tract?
SPINAL SHOCK Lose ALL reflex activity BELOW level of lesion (no direct damage just stop working) Leads to Flaccid paralysis - limbs become floppy with no muscular tone
53
Stage 2 of injury to lateral corticospinal tract?
RETURN OF REFLEXES aka. Hyperreflexia Reflexes become over-exaggerated! Rigid paralysis - high muscle tone
54
Why does Stage 2 of injury to lateral corticospinal tract lead to rigid paralysis?
Lower motor neurones BELOW level of lesion have been cut off from normal activating pathway SO have lowered their threshold and become more sensitive
55
Brown-Séquard syndrome?
A lesion in the spinal cord which results in weakness or paralysis (hemiparaplegia) on one side of the body and a loss of sensation (hemianesthesia) on the opposite side