The aim of this study was to define normal ranges of histological features in pediatric muscle in comparison with muscle demonstrating inflammatory changes. Sixteen pediatric muscle biopsy samples, considered normal by standard histology, were analyzed for the presence of inflammatory cells, and the expression of neonatal myosin and major histocompatibility complex (MHC) Class 1. Normal findings were defined for each feature. These data will facilitate quantitative analysis of inflammatory changes in pediatric muscle biopsy.