Test 2 Part1 Flashcards Preview

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Flashcards in Test 2 Part1 Deck (33)
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1
Q

What deep heating modality uses sound waves at high frequencies, penetrates the skin and subcutaneous fat, and also has mechanical effects?

A

Ultrasound

2
Q

What is the second most common heating modality used among chiropractors (63%)?

A

Ultrasound (moist hot packs is #1)

3
Q

What is the frequency range of most Ultrasound machines?

A

0.8-3.3 MHz

4
Q

How is the duty cycle for US calculated?

A

time sound is delivered divided by total treatment time

5
Q

Duty cycle of 100% =?

50% or 20%?

A

continuous US;

pulsed US

6
Q

What is the purpose of continuous Ultrasound? of Pulsed?

A

tissue healing;

mechanical/nonthermal effects

7
Q

Mechanical deformation of a crystal causes an electrical current to form…

A

Piezoelectric effect

8
Q

Alternating current is passed through a crystal resulting in very fast contraction and expansion of the crystal producing high frequency sound waves…

A

Reverse piezoelectric effect

9
Q

What is the ERA?

BNR?

A

Effective Radiating Area;

Beam Nonuniformity Ratio

10
Q

What is the term for the area of the sound head that produces sound energy which is always smaller than the size of the US head?

A

Effective Radiating Area

11
Q

What is the term for the ratio between the peak intensity of the US beam divided by the average intensity of the US beam?

A

Beam Nonuniformity Ratio

12
Q

What is the BNR used to determine?

A

comparison of the quality of different US machines

13
Q

What is the ideal BNR?

A

1:1 but within the range of 2:1-8:1 is acceptable

14
Q

T/F: The lower the BNR, the less uniform the intensity of the sound wave.

A

False; lower ratio equals more uniform

15
Q

What does PAMBNR stand for? and what does it describe?

A

Peak Area of the Maximum Beam Nonuniformity; describes the area of the sound head covered by the peak intensity

16
Q

T/F: Larger PAMBNR means less uniform heating.

A

True (peak intensity covers a larger area)

17
Q

T/F: Air is a poor conductor of US.

A

True, hence the use of gel and gel pads

18
Q

T/F: Underwater ultrasound is considered indirect ultrasound and should only be done in plastic buckets, not metal due to reflection.

A

True

19
Q

T/F: With US, more watts equals greater penetration.

A

False; equals more heating

20
Q

Frequency of US dictates depth of heating. What is the typical range?

A

1-3 MHz

21
Q

T/F: High frequency US (3MHz) is absorbed at a slower rate and therefore affects deeper tissues.

A

False; This is true of Low freq (1MHz), High freq is absorbed more rapidly affecting superficial tissues.

22
Q

T/F: More tissue healing occurs with continuous US than with pulsed.

A

True

23
Q

What is the difference b/w reflection and refraction?

A

reflection: reversal of direction
refraction: change from a straight path when passing obliquely from one medium to another

24
Q

T/F: The bending of US energy within tissue can lead to concentration of US at the point of reflection, such as where tendon joins bone.

A

False; should say point of REFRACTION

25
Q

T/F: 2-3 degrees C increase of tissues increases blood flow and reduces muscle spasm, whereas 4 degrees C increase alters viscoelastic properties of collagen.

A

True

26
Q

T/F: With US therapy, longer times are needed when lower intensities are used.

A

True

27
Q

Since superficial tissues cool faster than deeper ones, when should tissue manipulation or stretching occur with regard to US treatment?

A

Immediately after (while things are “warm and loose”)

28
Q

T/F: Pulsed US has been shown to stimulate fibroblast activity.

A

True

29
Q

What is the term for the movement of fluids along cell membranes due to mechanical pressure exerted by the sound waves?

A

Acoustical streaming

30
Q

What is the term for the rhythmic expansion and contraction of bubbles during repeated pressure changes over many acoustic cycles?

A

stable cavitation

31
Q

What is the term for the collapse of gas bubbles which may cause tissue damage, which is associated with low frequency high intensity US?

A

Unstable cavitation

32
Q

T/F: Metal implants are a contraindication for US, but plastic and/or cemented implants are not.

A

False; vice versa

33
Q

Why should you avoid using US over an Epiphyseal plate?

A

may alter bone growth