The invention relates to a needle for invasive medical use comprising a long extended cylindrical needle shaft (3) having an axis A and an outer surface area (2), with a short shaft end (4) at a first end of the shaft (5a) with a beveled tip (6) with a pointed end (7), and a needle hub (22) attached to a second end of the shaft (5b) comprising a device to indicate the location of the shaft end (4) during use inside a body. According to the invention, the needle comprises a flexible joint (11) with a notch (12) within the shaft (3) at the beginning of the shaft end (4). The said device is a displacement sensor (8) for detecting a displacement of the shaft end (4) relative to the rest of the shaft (3) resulted from a force F applied to the shaft end (4) when the needle hub (22) is moved and a signal conductor (24) to transmit the detected signals. The invention further describes a needle assembly (26) comprising such a needle (1) and a syringe (28) attached to said needle hub (22), whereas an evaluation unit (27) is connected to said the signal conductor (24).
