A survey of past literature has shown that there is a lack of reliable data for use in prediction of joint forces in the upper limb although this is desirable when developing joint replacements. Upper limb geometry has been analysed, leading to muscle moment arm data at the wrist and elbow. The variation of these moment arms during elbow flexion has also been examined. Analysis of the dimensions of muscles has enabled their relative strengths to be predicted, based on their ‘physiological cross-sections’. When used in conjuction with published emg data, this information will enable elbow and wrist joint forces to be estimated more realistically than has previously been possible.