{HEAD ~ A holder} for securely positioning a sensor on a protruding part of a human body, which sensor includes a light source transmitter and a receiver sensitive to radiation emitted by {TAIL ~ the transmitter}, comprising: 
{ HEAD ~ A holder } for securely positioning a sensor on a protruding part of a human body , which sensor includes a light source transmitter and a receiver sensitive to radiation emitted by { TAIL ~ the transmitter } , comprising :
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH