A magnetic reusable sensor is configured to attach to a tissue site so as to illuminate the tissue site with optical radiation and detect the optical radiation after attenuation by pulsatile blood flow within the tissue site. The sensor is configured to communicate with a monitor so as to calculate a physiological parameter corresponding to constituents of the pulsatile blood flow determined by the detected optical radiation. The sensor has a reusable emitter and a detector. A disposable wrap removably secures the emitter and the detector to a tissue site via magnetically enhanced receptacles fixedly mounted on the wrap and magnetically enhanced carriers housing the emitter and the detector.