Electromagnetic Spectrum

1. Electromagnetic Spectrum • This is the range of frequencies and wavelengths associated with radiant energy. • Each wavelength is color specific, the colors of the rainbow.R_O_Y_B_G_I_V • Other Forms Of Radiation Other Than Visible Light May Be Produced When An Electrical Force Is Applied

2. Spectrum Red Orange Yellow Green Blue Violet Prism

3. Infrared Spectrum Red Orange Yellow Green Blue Violet Ultraviolet

4. Electromagnetic Spectrum Longest Wavelength Lowest Frequency Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave Diathermy Infrared { LASER Visible Light Ultraviolet Shortest Wavelength Highest Frequency Ionizing Radiation

5. Wavelength And Frequency • Wavelength-Distance Between Peak Of One Wave and Peak of the Next Wave • Frequency-Number Of Wave Oscillations Or Vibrations Per Second (Hz, CPS, PPS) • Velocity=Wavelngth X Frequency

6. Electromagnetic Radiations Share Similar Physical Characteristics • Produced When Sufficient Electrical Or Chemical Forces Are Applied To Any Material • Travel Readily Through Space At An Equal Velocity (300,000,000 meters/sec) • Direction Of Travel Is Always In A Straight Line

7. Electromagnetic Radiations • In Addition, Other Forms Of Radiation Beyond Infrared And Ultraviolet Regions May Be Produced When An Electrical Force Is Applied • These Radiations Have Different Wavelengths And Frequencies Than Those In The Visible Light Spectrum

8. IR VISIBLE UV 150,000 7700 40001800A 7700A 3900A XRAY, GAMMA RAY DIATHERMY NEARFAR FAR<--NEAR Electromagnetic Spectrum

9. Characteristics of emr • 1. May be produced when sufficient electrical or chemical force is applied to any material. • 2. Travel readily through space at equal velocities • 3. Direction of travel is always in a straight line. • 4. May be reflected, refracted, absorbed or transmitted depending on the medium they strike

10. Electromagnetic Radiations Share Similar Physical Characteristics • When Contacting Biological Tissues May Be…

11. Electromagnetic Radiations Share Similar Physical Characteristics • When Contacting Biological Tissues May Be… • Reflected

12. Electromagnetic Radiations Share Similar Physical Characteristics • When Contacting Biological Tissues May Be… • Reflected • Transmitted

13. Electromagnetic Radiations Share Similar Physical Characteristics • When Contacting Biological Tissues May Be… • Reflected • Transmitted • Refracted

14. Electromagnetic Radiations Share Similar Physical Characteristics • When Contacting Biological Tissues May Be… • Reflected • Transmitted • Refracted • Absorbed

15. Laws Governing The Effects of Electromagnetic Radiations • Arndt-Schultz Principle • No Changes Or Reactions Can Occur In The Tissues Unless The Amount Of Energy Absorbed Is Sufficient To Stimulate The Absorbing Tissues

16. Laws Governing The Effects of Electromagnetic Radiations • Law Of Grotthus-Draper • If The Energy Is Not Absorbed It Must Be Transmitted To The Deeper Tissues • The Greater The Amount Absorbed The Less Transmitted and Thus The Less Penetration

17. Laws Governing The Effects of Electromagnetic Radiations • Cosine Law • The Smaller The Angle Between The Propagating Radiation And The Right Angle, The Less Radiation Reflected And The Greater The Absorption Source Source

18. Laws Governing The Effects of Electromagnetic Radiations • Inverse Square Law • The Intensity Of The Radiation Striking A Surface Varies Inversely With The Square Of The Distance From The Source Source 1 Inch 2 Inch

19. Heat Modalities Chapter 4 (still)

20. Heat is commonly classified into 3 major categories • Chemical action associated with cell metabolism • Electrical or magnetic currents as those found in diathermy devices • Mechanical action as found with ultrasound • The application of heat modalities is known as thermotherapy, and methods of heating are classified as being superficial or deep.

21. Superficial heating agents must be capable of increasing skin temp within a range of 104-113°F. • The transfer of heat to underlying tissues occurs via conduction, but superficial heating agents are limited to a depth of less than 2cm. • The use of heat is indicated in the subacute and chronic inflammatory stages of injury.

22. Because the effects of heat application are essentially opposite to those of cold, its use in the treatment of acute injuries should be avoided. • Applying heat to an active inflammatory cycle will ↑ the rate of cell metabolism and accelerate the amount of hypoxic injury

23. Superficial Infrared lamps Moist heat packs Paraffin baths Warm whirlpools and/or immersion Deep heat Microwave diathermy* Shortwave diathermy Ultrasound Classification of Heating Agents

25. Local effects of heat application • Vasodilation • ↑rate of cell metabolism • ↑ capillary permeablilty • ↑delivery of leukocytes • Edema formation • Removal of metabolic waste • ↑ elasticity of ligaments, capsules, and muscle • Analgesia and sedation of nerves • ↑nerve conduction • ↓muscle tone • ↓ muscle spasm • Perspiration

26. Some systemic effects of Heat exposure* • ↑ body temp • ↑ pulse rate • ↑ respiratory rate • ↓ blood pressure

27. Indications Subacute or chronic inflammatory conditions Reduction of subacute or chronic pain Subacute or chronic muscle spasm ↓ ROM Hematoma resolution Reduction of Joint contractures Contraindications Acute injuries Impaired circulation Poor thermal regulation Anesthetic areas Neoplasms Abnormal tissue, such as a tumor, that grows at the expense of healthy tissues General Indications/Contraindications

28. Effects on the injury response • Despite heat and cold produce many of the same outcomes, decreased pain, for example, the timing of when to begin using heat modalities is much more critical • If heat is applied too soon in the injury response cycle, the ↑cell metabolism causes an increase in the number of cells injured or destroyed because of hypoxia. • ↑ the inflammatory rate may possibly extend the acute and subacute stages

29. Cellular response • For each ↑ of 18°F in skin temp, the cells metabolic rate ↑ by a factor of 2-3. • As the cell’s metabolic rate ↑, so does its demand for oxygen and nutrients. • As with living organisms that consume energy, the amount of waste excreted from the cell ↑ as its activity ↑ • Also, ↑ metabolic rate ↑ tissue temp.

30. Blood and fluid Dynamics • Response of the body to heat is dilating local blood vessels • The amount of dilation being greater in superficial vessels than in the deeper vessels • ↑ capillary flow results in an ↑ supply of oxygen, nutrients, and antibodies to the effected area

31. The amount of edema is ↑, but the capability of removing it is greater • ↑ capillary pressure forces edema and harmful metabolites from the injured area • ↑ permeability aids in the re-absorption of edema and the dissolution of hematomas. • These wastes can drain into the venous or lymphatic systems • If venous and lymphatic return is not encouraged, further edema occurs.

32. Effects on inflammation • Local application of heat accelerates inflammation • Soft tissue repair is facilitated through an accelerated metabolic rate and ↑ blood supply • Blood flow must be ↑ to encourage the removal of cellular debris and to ↑ delivery of the nutrients necessary for the healing of tissues

33. ↑ oxygen stimulates the breakdown and removal of tissue debris and inflammatory metabolites • Nutrients are delivered to the area to fuel the cells, and there is also an ↑ in the delivery of leukocytes, encouraging phagocytosis.

34. Muscle Spasm and Tissue Elasticity • ↑ temperature reduces the primary and secondary muscle spindles’ sensitivity to stretch • ↓ the amount of muscle spasm present • Increasing blood flow and reducing local muscle metabolites further alleviate spasm • Most muscular tissues are not directly heated by superficial heating agents

35. ROM is subsequently improved by ↑ the extensibility of collagen and the viscosity and plastic deformation of tissues • This effect alone is not sufficient to ↓ contractures or ↑ the elasticity of healthy tissues • Neither anterior laxity of the knee nor hamstring flexibility has been shown to be affected by heat modalities alone • Tension, in the form of gentle stretching, is necessary to elongate muscle and capsular tissues while the tissues are still within the therapeutic range

36. Pain Control • Mechanical deformation and/or chemical irritation of nerve endings stimulate pain transmission • In acute injuries, the primary cause of pain is the mechanical damage done to the tissue in the area. • In the subacute and chronic stage of injury, ischemia and irritation cause chemical pain from certain chemical mediators • Mechanical pain is caused by increased swelling and the tension placed on the nerves by muscle spasm

37. Mechanical pain is decreased by reducing the pressure on the nerves , thus lessening the pain-spasm-pain cycle. • By encouraging venous and lymphatic return through the use of elevation and muscle contraction, the swelling is removed, decreasing interstitial pressure • An increase in temperature leads to a state of analgesia and sedation in the injured area by acting of free nerve endings. • Nerve fiber are stimulated, blocking the transmission of pain with a conterirritant effect. • This effect appears to last only as long as the stimulus of heat is applied