Patent ID: 7708694

Claim:
A cuff for measuring parameters of an appendage, including volume or change in volume of the appendage, comprising: a hollow, rigid tube having an inner surface and opposed ends; a bladder having an inner surface, an outer surface, and opposed ends, the ends of the bladder being sealed to the ends of the tube to create an enclosed internal volume between the inner surface of the bladder and the inner surface of the tube and an external volume defined by the outer surface of the bladder and surrounded by the internal volume, the bladder having a normal, relaxed state, in which the internal volume is filled with a fluid and a retracted state in which the fluid is evacuated from the internal volume; and at least one emitter and a plurality of detectors arranged in a linear array, the emitter and the detectors being positioned within the enclosed internal volume of the bladder and the emitter being separated from the closest detector by a minimum separation distance, wherein the emitter emits light at a first wavelength through the bladder into an appendage located within the external volume defined by the outside surface of the bladder, and the detectors detect light at the first wavelength that is back-scattered from the appendage and transmitted through the bladder to the respective detector positioned within the enclosed internal volume of the bladder; wherein the bladder has a sufficient wall thickness and is made from a single material tinted with pigments selected such that the bladder material will absorb the specific wavelengths of light emitted by the emitter to damp light piping laterally within the bladder from the emitter to each detector but also allow for sufficient transmission of light through the bladder into and out of the appendage to properly illuminate the tissue and to properly detect the light back-scattered from the appendage; and further wherein the emitter and detectors are attached to the inner surface of the bladder, the cuff contains at least one stiffener rib placed along the inner surface of the bladder parallel to the longitudinal axis of the tube, and the plurality of emitters and detectors are embedded in the rib.