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