{HEAD ~ A holder} for securely positioning {TAIL ~ 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 the transmitter, comprising: 
for securely positioning
{ HEAD ~ A holder } for securely positioning { TAIL ~ 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 the transmitter , comprising :
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL 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