US Flashcards
Transverse waves
Perpendicular to energy flow
Only travel through solids (bone)
What frequency is US?
> 20 kHz
- audible sound is 16kHz-20kHz*
- US is 0.75 and 3MHz*
Blood, body fluids, and fat (high water content) have…
Low acoustic impedance: high transmission, low absorption (waves go right through it)
travel to deeper tissues
Bone, muscle, peripheral nn., and collagen (high protein content) have…
High acoustic impedance: low transmission, high absorption
high absorption, so less is available for transmission to deeper tissues
1MHz
For deep tissues
Transmitted through superficial, absorbed by deep (2-5cm)
Good for high cutaneous fat and deep heat
3MHz
For superficial tissues
Absorbed by superficial (1-2cm)
Heats faster than 1MHz (higher frequency –> higher energy) ==> absorbed 3x faster than 1MHz - more comfortable
Can continuous US produce non-thermal effects?
At
Clinical application
Soft tissue healing and repair Scar tissue and joint contracture Chronic inflammation Bone healing Assessing stress fx's Wound healing
indications (17)
Acute and subacute conditions (non-thermal) Soft tissue healing and repair Scar tissue Joint contracture Chronic inflammation Increase extensibility of collagen Reduction of muscle spasm Pain modulation Increase BF Soft tissue repair Increase in protein synthesis Tissue regeneration Bone healing Repair of nonunion fx's Inflammation associated w/ myositis ossificans Plantar warts Myofascial trigger points
Contraindications (14)
Acute and post acute conditions (thermal) Areas of decreased temp sensation Areas of decreased circulation Vascular insufficiency Thrombophlebitis Eyes Reproductive organs Pelvis immediately following menses Pregnancy Pacemaker Malignancy Epiphyseal areas in young children Total joint replacements Infection
Longitudinal waves
|| to energy flow
Travel through both solids and liquids
