Physical examination of the hand is fundamental in the treatment of conditions that affect hand function. This is especially important in the pediatric population throughout all stages of development. There is a need for reliable and reproducible objective measures of pediatric intrinsic hand muscle strength. The manual muscle test (MMT) is traditionally used, but is highly subjective. With the relative size and strength discrepancy between an adult examiner and pediatric patient, subtle but clinically important changes are difficult to discern. While pinch and grip strength can be measured objectively with hand-held dynamometers, these measures combine the stronger extrinsic muscle forces with the smaller intrinsic muscles. To fill this clinical need, we developed PRIME (Peg Restrained Intrinsic Muscle Evaluator), a novel device designed specifically to quantify intrinsic hand muscle strength. The purpose of this study is to determine the inter-rater and intra-rater reliability of PRIME, as well as to establish normative values for intrinsic muscle strength in children.