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Definition : electromagnetic wave between 100nm –400nm
Classification of Ultraviolet radiation :

1. Ultraviolet A  (400nm - 315nm)
2. Ultraviolet B (315nm - 218nm)
3. Ultraviolet C (218nm – 100nm)

• Ultraviolet is similar to visiblelight in reflexion , refraction and absorption.

Ultraviolet physiological effect:


1- highly absorbed in air especially if wave length less than 280nm.
2- produce chemical changes in cells  rather than simple heat.
Production of Ultraviolet:
1- Low pressure Hg vapor.
2- Medium Pressure Hg vapor.
3- Kromyor lamp (Infrared through water)
4- Fluroscent lamp.
Physiological effects of Ultraviolet:
1. Erythmia : different from erythemaof IR and UV?
- Erythema of ultraviolet is more distinct (more sharp) because Ultraviolet is capillary vasodilator and IR is arteriols vasodilator.
- Ultraviolet could lead to cellular necrosis.
- Mast cells will produce Histamine and Histamine like substances due to U.V exposure (inflammation response)
- Ultraviolet has a latent period at least 2 hours.
2. Pigmentation:  Ultraviolet affect the secretion of melanine by melanocytes. and increase the migration of the melanine secreted.
3. U.V increase skin thickness : ultraviolet increase keratinocytes turn-over.
4. Desquamation
5. Increase production of vitamin D3 .
6. Antibiotic effect.
Ultraviolet indications:
1. Acne valgaris   --------- E2.
2. Psoriasis
3. Infected wounds like bed sores and ulcers.
Ultraviolet Contraindications:
1. Tumers.
2. Eyes area.
3. skin of deep X-ray therapy  .