There is provided an orthosis or exoskeleton system (200) comprising: one or more body mounting modules (102), the or each body mounting module being structured and arranged to, in use, be mounted to one or more parts of a body of a patient, the body mounting modules having different sizes or configurations with respect to each other； and one or more function modules (104), the or each function module being structured and arranged to provide a different sensing, charging or control function； the body mounting modules and the function modules each having an interfacing structure such that any said body mounting module is interchangeably couplable to any said function module.
