A noninvasive physiological sensor can include a first body portion and a second body portion coupled to each other and configured to at least partially enclose a user's finger. The sensor can further include a first probe coupled to one or more emitters and a second probe coupled to a detector. The first probe can direct light emitted from the one or more emitters toward tissue of the user's finger and the second probe can direct light attenuated through the tissue to the detector. The first and second probes can be coupled to the first and second body portions such that when the first and second body portions are rotated with respect to one another, ends of the first and second probes can be moved in a direction towards one another to compress the tissue of the user's finger.