#$%^&*AU2011201021B220130516.pdf#####ABSTRACT A system for assessing blood circulation in a subject's limb, comprising: detection means for detecting a signal dependent upon the arterial blood volume in a limb of the subject when the subject is in a first posture and also 5 when the subject is in a second posture, different to the first posture; and processing means for calculating a quantitative indicator that is dependent upon the ratio of the signal for the first posture to the signal for the second posture. C;poN.m-p SPEC-90831Q.doc