1. Which of them is a muscular disorder?
a) Paralysis
b) Muscular Dystrophy
c) Dementia
d) Alzheimer’s
Explanation: In Muscular Dystrophy, the muscles have become weak due to the absence or reduction of a protein, dystrophin, which disrupts normal muscle function. It causes muscle weakness and so they are not able to contract properly even if they receive the signal from the nerves.
2. An EMG acquires signals by the relaxing muscle fibers.
a) True
b) False
Explanation: When the muscles receive impulses, they work by contracting. Thus, we can say that contraction is an active process where energy is expanded while muscle straightening is a passive process where the muscle goes back to their original shape and structure. Thus, impulses are generated in the contraction process and thus are recorded by the electrodes.
3. The typical range of EMG can be _______
a) 0 – 1 mV
b) 1 – 5mV
c) 0 – 0.1 mV
d) 0.1 – 0.5 mV
Explanation: EMG signals are very faint. This can be because either the muscles generate the signals of small amplitudes or the signals have to go through the muscles before the electrodes can pick them. Thus, the signals acquired are of small amplitude and of a small range.
4. The use of EMG during surgery is to monitor _____________
a) the neuromuscular function with the neuromuscular blocking drug during general anaesthesia
b) the muscle tone during surgery
c) the muscle movement during surgery
d) the presence of impulses in muscles during surgery
Explanation: In order to allow blood to flow normally, muscles also play an important part. Thus, during surgery, EMG waves are taken to ensure the even spread when a general anesthesia is given. This anesthesia contains neuromuscular drugs so that the pain perception goes down during surgery and so the body does not react when in surgery. If this is monitored properly, it may cause pareses (temporary or permanent loss of muscular function) in future.
5. In order to take EMG, there exists a special electrode of 25μ diameter and 14 needles like pick up surfaces. What is this electrode used for?
a) Deeper penetration of muscle to take ECG
b) The larger surface area is covered
c) Multiple signals from the same muscle
d) Individual signals from individual muscle fibers
Explanation: The needles of the electrode increase the surface area and allow for all the needles to pick up signals from every fiber of the muscle individually. This way, the signals from every muscle fiber can be analysed and it is easier to point out the damaged area more accurately.
6. How does signal delay and triggering unit help in EMG?
a) It delays the incoming signal and allows the current signal to be processed properly
b) The delayed signals keep the system working for a longer time
c) The delayed signal is actually signal acquired from individual muscles
d) The delayed signal provides clarity in processing
Explanation: The signal delay and trigger unit of EMG is used to examine signal from individual muscle fibers. For this purpose, there is a special electrode of 25 micron diameter which has 14 needles like pick up surfaces. In order to receive and analyze signals properly, a delaying sweep is used. This allows for the signal to be taken from every needle individually, one at a time. This allows for better processing of the signal as well.
7. The number of leads necessary for an ECG is _________
a) 3
b) 6
c) 12
d) 24
Explanation: To have an ECG, the number of leads necessarily needed is 3. These three leads are placed on the four limbs in various combinations to derive the ECG. A 12 lead ECG is used for a greater in-depth analysis. It is used while taking a treadmill test.
8. Which of the four limbs acts like a ground and thus is not a part of the ECG test?
a) Right Arm
b) Left Arm
c) Right Leg
d) Left Leg
Explanation: In the various combinations to take ECG, the right leg is considered to be grounded and so no leads are placed on it to take an ECG. It may sometimes have a lead line for grounding but otherwise, that leg does not take part in ECG testing.
9. What result do the various combinations of limb leads give?
a) Einthoven’s Triangle
b) Beethoven’s Triangle
c) Bermuda’s Triangle
d) Electrical Triangle
Explanation: The leads are arranged in 3 combinations making one limb positive, one negative and the third as a neutral. There is a vector arrow drawn from the negative side to the positive side. The three arrangements thus result in a triangle which is called the Einthoven’s triangle.
10. The most common placement of the leads from the Einthoven’s triangle is __________
a) Positive Left Arm and Negative Right Arm
b) Positive Left Leg and Negative Right Arm
c) Positive Left Leg and Negative Left Arm
d) Positive Right Arm and Negative Left Leg
Explanation: The Einthoven’s triangle forms a cyclic vector in form of direction. The most important readings are from the 2nd placement of leads in which the Left Leg is positive, the Right Arm is Negative and the Left Arm is neutral. The vector direction is from the right arm to the left leg.