1. By B. Nelson

2. Definition of IR radiation Radiation: the process of emitting energy in waves from a source Portion of the electromagnetic spectrum with wavelength of 780 nm – 100,000 nm

3. Physiological effects Cutaneous vasodilation Increase nerve conduction velocity 50% of the IR radiation of 1200nm wavelength penetrates beyond 0.8mm and interact with subcutaneous capillaries and cutaneous nerve endings.

4. Types of IR generators 2 types of generators: 1) Luminous generator 2) non luminous generator

6. Infrared Lamp

7. Infrared lamp

8. Therapeutic effects Decreases pain Increase joint flexibility– increase joint ROM Duration of treatment application ranges from 15 – 30 minutes

9. Indications Used when patient cannot tolerate pressure from another type of modality

10. Contraindications Where is decreased sensation Peripheral Vascular Disease with compromised circulation Over a tumor

11. Increase in tissue temperature Is influenced by the amount of radiation that penetrate the tissue The power and wave length of the radiation The distance of the radiation source from the tissue The angle of incidence of the radiation to the tissue The absorption coefficient of the tissue

12. Absorption of IR Intensity reaching the skin is greatest when : 1) the source of radiation is closest to the skin 2)the radiation beam is perpendicular to the skin surface (optimal absorption occurs when the rays strike perpendicularly)

13. Absorption coefficient IR absorption coefficient are mainly affected by skin colour ( darker skin will absorb more)

14. Absorption of IR Absorption is affected by: 1) the amount of melanin in the skin ( darker skin absorbs more radiation than lighter skin) 2)skin texture 3) dryness, smoothness

15. Adverse effects of IR radiation Dries the skin more than other modalities Does not treat uneven body parts well due to uneven heating

16. Laws governing the effects of electromagnetic radiation 1)Arndt-Schultz principle : no reaction or changes can occur in the body tissues if the amount of energy absorbed is insufficient to stimulate the absorbing tissues

17. 2) Law Grotthus –Draper:if the energy is not absorbed by the superficial tissue, it will penetrate to the deeper tissues

18. Cosine Law The cosine law states that the smaller the angle between the propagating ray and the right angle,the less radiation reflected and the greater absorbed

19. Inverse square law States that the intensity of the radiation striking the particular surface varies inversely with the square of the distance from the source

20. note The modalities that emit radiations with relatively longer wavelength have the ability to transmit energy through the superficial tissue layers,thus penetrating to the deeper tissues where it is absorbed

21. Method of application

22. Contrast packs/bath Are applied by alternately immersing an area first in warm water/hot and then in cool/cold water Published data on this modality is lacking

23. Indications Chronic oedema Subacute trauma Sprains, strains, or tendinitis Changing a modality from cold to hot to facilitate a mild temperature increase

24. Therapeutic effects Increase blood flow to the injured area without the accumulation of additional oedema Oedema is decreased

25. Method of application 3:1 or4:1 ratio of hot to cold for 20 minutes

26. Physiologic response Vasoconstriction and vasodilation

27. References Physical Agents in Rehabilitation: From Research to Practice: Michelle H. Cameron Physical Agents: Theory And Practice: Barbara J. Behrens, Susan L. Michlovitz Therapeutic Modalities in Rehabilitation by William Prentice