A simplified technique for determining foot progression angle in children 4 to 16 years of age.

Foot progression angle was determined in 400 normal children ranging in age from 4-16 years using a new clinically available assessment technique. Children ages 4-5 were found to have an average out-toeing of 2.8 degrees (1 STD = 6.9 degrees). The average foot progression angle increased with age to 7.3 degrees at age 16 (1 STD = 4.4 degrees). Univariate analysis of these data found that age, tibial alignment, arch index, and the ratio of body weight to body height significantly affected foot progression angle. If, for children 4-16 years of age, two standard deviations from the average of 4.2 degrees out-toeing is taken as a normal range of variance, -8 degrees (in-toeing) to +16.4 degrees (out-toeing) would be acceptable for these ages. The measurement technique is described in detail, and the normative values and age-specific results are reviewed and discussed.

The 1986 and 1988 UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) reports: findings and implications.

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has published a substantive series of reports concerning sources, effects, and risks of ionizing radiation. This article summarizes the highlights and conclusions from the most recent 1986 and 1988 reports. The present annual per person effective dose equivalent for the world's population is about 3 mSv. The majority of this (2.4 mSv) comes from natural background, and 0.4 to 1 mSv is from medical exposures. Other sources contribute less than 0.02 mSv annually. The worldwide collective effective dose equivalent annually is between 13 and 16 million person-Sv. The Committee assessed the collective effective dose equivalent to the population of the northern hemisphere from the reactor accident at Chernobyl and concluded that this is about 600,000 person-Sv. The Committee also reviewed risk estimates for radiation carcinogenesis which included the new Japanese dosimetry at Hiroshima and Nagasaki. These data indicate that risk coefficient estimates for high doses and high dose rate low-LET radiation in the Japanese population are approximately 3-10% Sv-1, depending on the projection model utilized. The Committee also indicated that, in calculation of such risks at low doses and low dose rates, a risk-reduction factor in the range of 2-10 may be considered.