Ischaemic nerve block (Practical)

Question 1

What is the pressure that the cuff needs to be inflated to during experiment?

Answer 1

160 mmHg

Question 2

Why should subject raise arm and hands over head for 1 minute prior to inflation of cuff?

Answer 2

Empty blood from veins to prevent distension and discomfort

Question 3

What aspects iof somatosensation are tested?

Answer 3

1. Light touch: Cotton wool
2. Deep pressure
3. Vibration
4. Position: Bending and straigntening fingers

Question 4

What is the order that functions are lost from the ischaemic arm?

Answer 4

1. Somatosensation is lost first
2. Paralysis of muscles
3. Pain and temperature is lost last

Question 5

What is the pattern of spread of functional loss throughout the upper limb?

Answer 5

Distal → Proximal

Question 6

What type of functions are assoicated with large diameter fibres that are lost first?

Answer 6

1. Aα: Muscle strength
2. Aβ: Touch, vibration, proprioception

Question 7

What types of functions are associated with small myelinated fibres?

Answer 7

1. Aδ: Pin-prick pain, cold
2. C: Warmth, itch

Question 8

Which channel is opened by caspaicin?

Answer 8

TRPV1

Question 9

Which channel is opened by mustard/horseradish?

Answer 9

TRPA1

Question 10

What is the density of Meissner’s corpuscules in adult skin?

Answer 10

10-30 mm^-2 (decreases with age)