The order and time of closure of the epiphysial plate in the female rat (Charles River CD strain) from age 60–120 days are presented. The state of the epiphysial fusion zone was observed stereomicroscopically on cleared and Alizarin Red S stained intact skeletons, using the method of Dawson (10, 11). This method of determining the skeletal maturation is compared with others using radiography and histologic sections. The usefulness of assessing skeletal maturation in rats by the number of epiphysial fusions and the requirements for statistical analyses are discussed. Reasons are advanced for selecting 21 epiphyses chosen by means of consistency in the sequence of closure and by reliability in determining the state of closure. Two nonparametric statistical tests are suggested for assessing skeletal maturation. Skeletal maturation in the female rat is advanced in relation to that of the male rat.

This content is only available as a PDF.
You do not currently have access to this article.