In order to understand the mechanics of the human musculoskeletal system, quantitative data on the functional anatomy of the muscles related to the joint are necessary. Several important biomechanical parameters of the muscles controlling the elbow joint were determined. Serial cross-sectional anatomy analysis was used to obtain the centroid and thus the moment arms of each of the muscles along the upper arm and at the elbow joint. Muscle volume and true fiber length at the resting position were also measured. From these data, the physiological cross-sectional areas were calculated. The volume provided the information on the work capacity of the muscles. The physiological cross-sectional area provided the potential tension which the muscle can generate.