Somatosensory Pathways (NB.044) (Large group)

Question 1

Sensory area one

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Question 2

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Question 3

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Question 4

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Question 5

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Question 6

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Question 7

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Question 8

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Question 9

When you are dealing with neurological case (sensory) you have to answer 2 important questions:

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-Where is the lesion?

-What is the lesion?

Question 10

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Question 11

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Question 12

Syringomyelia

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Question 13

Syringomyelia

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Question 14

1- Name the pattern of analgesia seen in this patient?

Answer 14

Jacket - like dissociated sensory loss.

Question 15

2- Explain the sensory loss?

Answer 15

The sensory loss is due to damage of the crossing fibers of the lateral and ventral spinothalamic tract by the gliosis or fibrosis around the central canal (loss of pain & temperature) while the dorsal column tract is intact (tactile sensations & proprioception).

Question 16

3. Define the dermatomes affected?

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Question 17

4. If you examine for light touch, what would be the finding?

Explain?

Answer 17

It would be partially affected as it is carried to a little extent by the dorsal column (which is intact) together with the ventral spinothalmic tract (which is affected).

Question 18

5. What is the diagnosis of this case?

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Syringomyelia.

Question 19

6. What is the site of the lesion ?

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Question 20

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Question 21

Tabes Dorsalis

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Question 22

Tabes Dorsalis

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Question 23

an affection of Tabes Dorsalis…. Daignose and explain the pathology

Answer 23

(Argyll Robertson pupil)

where the pupil is irregular, shows miosis in response to near objects (intact accommodation) but no miosis in response to light (lost pupillary light reflex).

Question 24

1- Explain the loss of position and vibration sensations?

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The lost position and vibration sensations are due to compression on the afferent fibers (Aβ fibers) that carry the sensations at the dorsal root by the lesion, leading to failure of sensory impulse transmission to the cortex.

Question 25

2- Explain the absent deep reflexes?

Answer 25

The absent deep reflexes are due to compression on the afferent fibers of reflexes (muscle spindle reflex) at the dorsal root.

Question 26

3- Explain the positive Romberg’s sign?

Answer 26

The positive Romberg’s sign is due to loss of proprioceptive sensations from lower limbs leading to inability to maintain balance while closing eyes.

Question 27

4- Why does this patient complain of pain?

Answer 27

The patient complained of pain due to irritation of pain conducting fibers at the dorsal root by the inflammatory process, leading to transmission of impulses through the fibers to the brain and perception of pain.

Question 28

5- list the other effects of a dorsal column lesion in this area that were not mentioned in this case?

Answer 28

-Loss of fine touch

-Loss of stereognosis

-Loss of superficial reflexes (flexor withdrawal)

-Loss of visceral reflexes

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Question 32

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