Abstract: A marker loading assembly for transferring an elongated positioning marker from a loader needle of said assembly into an insertion needle of a medical insertion device, the marker loading assembly comprises an elongated hollow housing having a manoeuvring end and a marker transfer end, and a loader needle mounted within said loading assembly along a longitudinal axis of said assembly, said loader needle being adapted to receive and hold said positioning marker until the positioning marker is transferred to said insertion needle, a transfer opening provided at the marker transfer end and being adapted to receive a distal end of the insertion needle, said transfer opening being provided with a shape gradually opening up in a direction away from said manoeuvring end, and said transfer opening at its narrow end leading to a transfer channel arranged along said longitudinal axis, and wherein the transfer channel has a circular cross-sectional shape having a diameter slightly larger than an outer diameter of the in