ABSTRACT
The prevalence estimates of back disorders vary depending on assessment methods and population characteristics. Most commonly described entity is low back pain (LBP), which is intermittent in nature. For such an entity, instead of point prevalence, a period prevalence, i.e. the proportion of the population experiencing low back pain during a certain period of time, is often presented. The period of observation can vary from lifetime to the past year or one month. Most data on back disorders are based on questionnaire surveys. Only in a few community studies has clinical examination been used to verify the existence of back disorders. On the other hand. it is a common understanding that with a thorough clinical examination some rare, specific causes of back pain. such as malignancies, infections, inflammatory diseases, or fractures can be identified. In addition to that, only a differentiation between sciatica and nonspecific back symptoms can be done (Bigos et al. 1 994).
