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Flashcards in Spinal Cord Deck (46):
0

What is the sp. cord derived from?

embryonic neural tube

1

What is the arterial supply of the sp. cord?

branches of the ant. spinal a.
post. spinal a.

(also gets supply from multiple radicular aa.)

2

Where do the ant. & post. spinal aa. branch from?

vertebral arteries

3

The spinal cord extends from the _________ to the _________.

medulla at the foramen magnum; lower border of L1

4

What are the 2 enlargements? What are their functions?

Cervical - innervate upper extremities
Lumbar - innervate lower extremities

5

Conus medullaris

L1 & L2 vertebrae

6

Site for lumbar puncture:

L4-L5 vertebrae

7

Filum terminale

pia mater from the conus medullaris to the coccygeal ligament

8

Cauda equina

lumbosacral roots surrounding the filum terminale

9

How is the sp. cord segmented?

31 pairs of spinal nerves in 31 segments:
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

10

All spinal nerves innervate a single dermatome except?

C1

11

What is referred pain?

convergence of somatic and visceral afferents

12

Spinal nerves exit the _________ via the ____________ (location of ______).

vertebral canal; intervertebral foramina; DRG

13

Spinal cord indentations:

Anterior median fissure
posterior median sulcus/septum
posterolateral sulcus
posterior intermediate sulcus

14

What lies in the ant. median fissure?

ant. spinal artery and vein

15

____________ (entry of dorsal roots)
____________ (exit of ventral roots)

posterolateral sulcus
anterolateral sulcus

16

The ______________ is found in the ______________ only and is the separation of between 2 major ascending tracts

posterior intermediate sulcus; cervical and thoracic

17

What is the largest area of the spinal cord? The smallest?

cervical enlargement
sacral level

18

White matter is subdivided into:

Posterior funiculus (dorsal column)
Lateral funiculus (column)
Anterior funiculus (column)

19

Posterior funiculus:

Ascending somatosensory fibers:
1) Fasciculus gracilis (sacral & lumbar)
2) Fasciculus cuneatus (thoracic & cervical)

20

What is the function of ascending somatosensory fibers?

fine touch
vibration
two-point discrimination
proprioception

21

Lateral funiculus:

Descending tracts to the spinal cord:
lateral corticospinal tract
rubrospinal tract

22

What is the largest and most important tract? What will happen if this tract is lesioned?

lateral corticospinal tract

if lesioned, spastic paralysis will occur on the ipsi lateral side at the spinal cord level

23

The rubospinal tract is a(n) ____________ tract

contralateral

24

The posterior funiculus is a(n) __________ tract.

ipsilateral

25

What will happen if the posterior funiculus is lesioned?

There will be loss of somatosensory sensation on the ipsi side below the level of the lesion

26

Ascending tracts from the spinal cord:

spinothalamic tracts = anterolateral tract
posterior spinocerebellar tract

27

Spinothalamic tracts:

contralateral tract
pain, temp., crude touch

if lesioned: loss of sensation on the contralateral side

28

Posterior spinocerebellar tract:

ipsilateral tract (from spinal cord to cerebellum)
stretch, touch and pressure sensation

if lesioned: loss of sensation on the ipsilateral side

29

Anterior funiculus:

smaller ascending and descending tracts
crossing of the spinothalamic tracts

30

Gray matter is subdivided into:

dorsal horn
ventral horn
lateral horn

31

Dorsal horn:

Sensory:
receives sensory input
mediates synapses
gives rise to ascending sensory pathways

33

Ventral horn:

Motor:
• α motoneurons
• γ motoneurons
• interneurons
• Neurons innervate extrafusal & intrafusal muscle fibers

34

Lateral horn:

Intermediolateral cell column (T1-L2/L3)
Thoracolumbar sympathetic outflow (preganglionic)

35

There are ____ cellular laminae

9

36

Dorsal horn: I - VI

All sensory:
I - marginal zone (pain & temp)
II - substantia gelatinosa (interneurons)
III - V - mechanical visceral and noxious stimuli
VI - prominent only at enlargements

37

Which laminae give rise to the anterolateral tract?

I, V and some VII

38

Intermediate zone: dorsal VII

Medial: Clarke's nucleus (C8-L3)
• gives rise to dorsal spinocerebellar tract

Lateral:
• Intermediolateral cell column (T1-L2/L3) - preganglionic sympathetic
• Sacral autonomic nuclei (S2-S4) - preganglionic parasympathetic

39

Ventral horn:

ventral VII, VIII & IX
• Motor neuronal groups in lamina IX: innervate truncal & limb muscles

40

General functional significance of the spinal cord:

1) receives the primary sensory afferent inputs from the DRG; relays them to the brain stem, cerebellum or the thalamus; may or may not synapse within the spinal cord

2) α & γ motorneurons that innervate extrafusal & intrafusal muscles

3) mediates spinal reflexes

4) intermediolateral cell column from T1 to L2/L3 that gives rise to preganglionic sympathetic fibers; synapse in the paravertebral & prevertebral ganglia

5) preganglionic parasympathetic neurons in S2-S4; synapse in terminal ganglia within walls of the pelvic viscera

6) major sensory & motor ascending and descending tracts run through it

41

Lesions of the spinal cord:

dorsal root lesions
ventral root lesions
spinal cord hemisection (Brown-Sequard syndrome)
spinal cord transection
syringomyelia

42

Dorsal root lesions:

hypesthesia or anesthesia

43

Ventral root lesions:

weakness/flaccid paralysis & atrophy of muscles
involvement of autonomic preganglionic fibers may result in autonomic dysfunction

44

Spinal cord hemisection:

loss of fine touch, vibration and propioception ipsilateral to & below lesion
loss of pain & temp. contralateral to & below lesion
spastic paralysis ipsi to & below lesion

45

Spinal cord transection:

destruction of ascending and/or descending tracts produces sensory, motor & mixed deficits

46

Syringomyelia:

damage crossing fibers around the central canal