Neuro - Anat & Phys (Spinal Anatomy & Motor Signs) Flashcards Preview

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Flashcards in Neuro - Anat & Phys (Spinal Anatomy & Motor Signs) Deck (37)
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1
Q

How many spinal nerves are there? List them by category.

A

There are 31 spinal nerves in total: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal.; Think: “31, just like 31 flavors of Baskin-Robbins ice cream!”

2
Q

Where do spinal nerves exit?

A

Nerves C1-C7 exit above the corresponding vertebra. All other nerves exit below (e.g., C3 exits above the 3rd cervical vertebra; L2 exits below the 2nd lumbar vertebra)

3
Q

What is Vertebral disc herniation? Where does it usually occur?

A

Vertebral disc herniation - nucleus pulposus (soft central disc) herniates through annulus fibrosus (outer ring); usually occurs posterolaterally at L4-L5 or L5-S1

4
Q

What is the lower extent of the spinal cord in adults?

A

In adults, spinal cord extends to lower border of L1-L2 vertebrae.

5
Q

What is the lower extent of the subarachnoid space?

A

Subarachnoid space (which contains the CSF) extends to lower border of S2 vertebra

6
Q

Where is a Lumbar puncture usually performed?

A

Lumbar puncture is usually performed between L3-L4 or L4-L5 (level of cauda equina);

7
Q

What is the goal of a lumbar puncture? How is this accomplished?

A

Goal of lumbar puncture is to obtain sample of CSF without damaging spinal cord. Think: “To keep the cord alive, keep the spinal needle between L3 and L5.”

8
Q

Where are legs located in the lateral corticospinal tracts? In what other tract are they located in the same place?

A

Legs (Lumbosacral) are Lateral in Lateral corticospinal, spinothalamic tracts

9
Q

How is the dorsal column (somatotopically) organized?

A

Dorsal column is organized as you are, with hands at sides. Arms outside, legs inside.

10
Q

What function does lateral corticospinal tract serve? What is another tract that serves this same function?

A

DESCENDING: (1) Lateral corticospinal tract (2) Anterior corticospinal tract; Voluntary motor

11
Q

What function(s) does the dorsal column serve?

A

ASCENDING: Dorsal column - Pressure, vibration, touch, proprioception

12
Q

What are 2 ascending tracts near the anterior of the spinal cord? What are their functions?

A

ASCENDING:(1) Lateral spinothalamic tract - Pain, temperature; (2) Anterior spinothalamic tract - Crude touch, pressure

13
Q

What are the names of the white matter in the dorsal column associated with the lower body/legs versus upper body/arms?

A

(1) Fasciculus gracilis (lower body, legs) (2) Fasciculus cuneatus (upper body, arms)

14
Q

Draw the spinal cord and label its associated tracts: (1) ASCENDING: Dorsal column (2) ASCENDING: Lateral spinothalamic tract (3) ASCENDING: Anterior spinothalamic tract (4) DESCENDING: Lateral corticospinal tract (5) DESCENDING: Anterior corticospinal tract (6) Fasciculus gracilis (7) Fasciculus cuneatus (8) Gray matter (9) Anterior horn (10) Posterior horn (11) Intermediate horn sympathetics (T1-L2/L3) (12) White matter.

A

See p. 465 in First Aid 2014 for visual

15
Q

What is the orientation of cervical versus sacral in the Lateral corticospinal tract? What other tract shares this same orientation?

A

Cervical = medial; Sacral = lateral; Lateral spinothalamic tract

16
Q

What should you remember about ascending tracts?

A

Remember, ascending tracts synapse and then cross

17
Q

What kind of tract is the Dorsal column? What is its function?

A

Ascending: pressure, vibration, fine touch, and proprioception

18
Q

What kind of tract is the Spinothalamic tract? What is (are) its function(s) ?

A

Ascending; Lateral - Pain, temperature; Anterior - Crude touch, pressure

19
Q

What kind of tract is the Lateral corticospinal tract? What is its function?

A

Descending: Voluntary movement of contralateral limbs.

20
Q

What is the route taken by the Dorsal column? Include neurons and synapses in order.

A

1ST-ORDER NEURON: Sensory nerve ending –> cell body in dorsal root ganglion –> enters spinal cord, ascends ipsilaterally in dorsal column; SYNAPSE 1: Ipsilateral nucleus cuneatus or gracilis (medulla); 2ND-ORDER NEURON: Decussates in medulla –> ascends contralaterally in medial lemniscus; SYNAPSE 2: VPL (thalamus); 3RD-ORDER NEURON: Sensory cortex

21
Q

What is the route taken by the Spinothalamic tract? Include neurons and synapses in order.

A

1ST-ORDER NEURON: Sensory nerve ending (Adelta and C fibers) (cell body in dorsal root ganglion) –> enters spinal cord; SYNAPSE 1: Ipsilateral gray matter (spinal cord); 2ND-ORDER NEURON: Decussates at anterior white commissure –> ascends contralaterally; SYNAPSE 2: VPL (thalamus); 3RD-ORDER NEURON: Sensory cortex

22
Q

What is the route taken by the Lateral corticospinal tract? Include neurons and synapses in order.

A

1ST-ORDER NEURON: UMN: cell body in primary motor cortex –> descends ipsilaterally (through internal capsule), most fibers decussate at caudal medulla (pyramidal decussation) –> descends contralaterally; SYNAPSE 1: Cell body of anterior horn (spinal cord); 2ND-ORDER NEURON: LMN: leaves spinal cord; SYNAPSE 2: NMJ

23
Q

What is the 1st-order neuron for the Dorsal column, and where does it travel?

A

1ST-ORDER NEURON: Sensory nerve ending –> cell body in dorsal root ganglion –> enters spinal cord, ascends ipsilaterally in dorsal column

24
Q

What is the 2nd-order neuron for the Dorsal column, and where does it travel?

A

From synapse 1 (ipsilateral nucleus cuneatus or gracilis (medulla)), 2ND-ORDER NEURON: Decussates in medulla –> ascends contralaterally in medial lemniscus

25
Q

What is the 3rd-order neuron for the Dorsal column?

A

From synapse 2 (VPL (thalamus)), 3RD-ORDER NEURON: Sensory cortex

26
Q

What are the 2 synapses of the Dorsal column?

A

SYNAPSE 1: Ipsilateral nucleus cuneatus or gracilis (medulla); SYNAPSE 2: VPL (thalamus)

27
Q

What is the 1st-order neuron for the Spinothalamic tract, and where does it travel?

A

1ST-ORDER NEURON: Sensory nerve ending (Adelta and C fibers) (cell body in dorsal root ganglion) –> enters spinal cord

28
Q

What is the 2nd-order neuron for the Spinothalamic tract, and where does it travel?

A

From synapse 1 (ipsilateral gray matter (spinal cord)), 2ND-ORDER NEURON: Decussates at anterior white commissure –> ascends contralaterally

29
Q

What is the 3rd-order neuron for the Spinothalamic tract?

A

From synapse 2 (VPL (thalamus)), 3RD-ORDER NEURON: Sensory cortex

30
Q

What are the 2 synapses of the Spinothalamic tract?

A

SYNAPSE 1: Ipsilateral gray matter (spinal cord); SYNAPSE 2: VPL (thalamus)

31
Q

What is the 1st-order neuron for the Lateral corticospinal tract, and where does it travel?

A

1ST-ORDER NEURON: UMN: cell body in primary motor cortex –> descends ipsilaterally (through internal capsule), most fibers decussate at caudal medulla (pyramidal decussation) –> descends contralaterally

32
Q

What is the 2nd-order neuron for the Lateral corticospinal tract, and where does it travel?

A

From synapse 1 (cell body of anterior horn (spinal cord)), 2ND-ORDER NEURON: LMN: leaves spinal cord

33
Q

What are the 2 synapses of the Lateral corticospinal tract?

A

SYNAPSE 1: Cell body of anterior horn (spinal cord); SYNAPSE 2: NMJ

34
Q

What are the motor neuron signs for an UMN lesions as it applies to the following: (1) Weakness (2) Atrophy (3) Fasciculations (4) Reflexes (5) Tone (6) Babinski (7) Spastic paralysis (8) Flaccid paralysis (9) Clasp knife spasticity?

A

UMN lesion: (1) + (2) - (3) - (4) Increased (5) Increased (6) + (7) + (8) - (9) +; Think: “Upper MN = everything UP (tone, DTRs, toes).”

35
Q

What are the motor neuron signs for an UMN lesions as it applies to the following: (1) Weakness (2) Atrophy (3) Fasciculations (4) Reflexes (5) Tone (6) Babinski (7) Spastic paralysis (8) Flaccid paralysis (9) Clasp knife spasticity?

A

LMN lesion: (1) + (2) + (3) + (4) Decreased (5) Decreased (6) - (7) - (8) + (9) -; Think: “Lower MN = everything lowered (less muscle, decreased muscle tone, decreased reflexes, downgoing toes)”

36
Q

What are Fasciculations? With which type of motor neuron lesion do they occur?

A

Fasciculations = muscle twitching; Lower MN

37
Q

In what patient population is a positive Babinski normal?

A

Positive Babinski is normal in infants

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