A device for introducing a medium or an instrument into the human body, in particular port or trocar for the human eye, comprising a connection body (1), a passage (2) configured in the connection body (1) and a probe (3) connecting to the passage (2), wherein the probe (3) serves for introducing into the body and the connection body (1) on the side facing the probe (3) serves for arrangement outside of the body and on the side facing away from the probe (3) serves for introducing or coupling a tube, instrument or the like, is characterised in that the connection body (1) has a recess or cutout (4) extending from the edge region to the passage (2) or to the probe (3), which tapers towards the passage (2).
