Patent ID: 8346330

Claim:
An optical sensor configured to provide an indication of a physiological parameter comprising: a plurality of emitters that transmit light having a plurality of wavelengths; a detector that outputs a sensor signal, the sensor signal is at least substantially responsive to the emitter transmitted light after attenuation by pulsatile blood flow perfused within a fingernail bed underneath the fingernail; and at least one reflection detector that outputs at least one sensor position signal, the sensor position signal including a sensor-on condition indicating that the attachment assembly has positioned the emitters generally centered over a fingernail, the detector on a fingertip opposite the fingernail and the at least one reflection detector over the fingernail, the at least one sensor position signal, in the sensor-on condition, is at least substantially responsive to the emitter transmitted light after reflection off of the fingernail; an attachment assembly that attaches the emitters, the detector and the at least one reflection detector onto a tissue site.