Practical 6: EMG, reflexes and human nerve conduction velocity

Question 1

What does ADM stand for?

Answer 1

Abductor digiti minimi

Question 2

where are the 2 electrodes applied to record the ADM?

Answer 2

on the lateral surface of the hand about 1cm apart, just over the ADM muscle

Question 3

where is the green ground electrode placed when measuring the ADM?

Answer 3

the bony region of the wrist

Question 4

how do you obtain a trace of grounded voluntary activity of the ADM?

Answer 4

begin by recording a short period of relaxation of the ADM muscle to give a steady baseline
- do 3/4 contractions, increasing the strength of contraction each time

Question 5

How is the stimulation of the ulnar nerve done?

Answer 5

a stimulating electrode is used to excite nerve fibres in the Ulnar nerve

• put a small amount of electrode gel on the stimulating electrode- spread thinly
• place the electrode at the groove at the back of the elbow- pressing firmly against skin
• click start to stimulate the nerve and study 3 different amplitudes

Question 6

How is the measurement of conduction velocity of ulnar motor fibres done?

Answer 6

recording are needed at 2 well-separated stimulating sites along the nerve
stimulate ulnar nerve at wrist as well as back of elbow
- record 5-10 cycles
- measure the time taken and the distance between the 2 points of stimulation
- calculate conduction velocity in metres per second