A pulse oximetry sensor includes reusable and disposable elements. To assemble the sensor, the reusable element is snapped or slid within assembly mechanisms of the disposable element. In one embodiment, the reusable element includes protrusions while the disposable element includes tabs which receive the protrusions. In another embodiment, the reusable element includes neck portions and the disposable element includes straps which receive the neck portions. In any event, the assembly provides longitudinal movement between elements.