Abstract: Techniques for non-invasive detection of compartment syndrome (CS) in a subject, includes an apparatus having a structural body configured to be held in a human hand. The structural body includes a subject contact element that is not in contact with the human hand and is configured to contact but not penetrate a skin layer of a subject. The apparatus also includes an optical sensor configured to detect oxygen saturation at a plurality of depths of a subject in contact with the subject contact element. The optical sensor includes at least one light emitting diode (LED) and multiple photo detectors at corresponding different distances from the LED.