Medical needle

A needle comprising:

• terminals located at or near its tip that are connected to an impedance calculating circuit and configured to enable the impedance calculating circuit to apply an alternating current input electrical signal to the terminals, the terminals further configured to enable the impedance calculating circuit to measure a resultant electrical signal and calculate an impedance of biological tissue surrounding the tip;
• light transmitting media extending along the needle that is connected to a light circuit, the light circuit including an emitter/detector pair for transmitting light from the emitter, along the media, and emitting the light from the tip and for transmitting a reflection of the emitted light from the tip to the detector, wherein the light circuit is configured to calculate light absorption of the tissue;
• and
• wherein the impedance calculating circuit is configured to determine the type of biological tissue from both of the calculated impedance and the calculated light absorption of the tissue.