An apparatus for simulating an insertion of an elongated instrument into a subject, comprising: a frame defining an enclosure, the frame extending between two end walls along a first axis and two lateral walls along a second axis, each of the two end walls being provided with an insertion aperture and each of the two lateral walls being provided with an insertion hole , the insertion apertures having a first dimension and the insertion holes having a second dimension for receiving therein elongated instruments having different cross-sectional sizes; a first hollow guiding structure extending between the two end walls within the frame and being aligned with the insertion apertures and defining a first passageway for receiving and guiding the elongated instrument inserted through one of the insertion apertures , and a second hollow guiding structure extending between the two lateral walls within the frame and being aligned with the insertion holes and defining a second passageway for receiving and guiding the elongated instrument inserted through one of the insertion holes , the two hollow guiding structures intersecting each other at an intersection zone; and a sensing unit contained within the frame and configured for measuring at least one of a displacement of the elongated instrument and a rotation of the elongated instrument, the sensing unit being positioned at the intersection zone for performing the measurement of the at least one of the displacement and the rotation at the intersection zone, the sensing unit being configured to perform said measurement within the first passageway and the sensing unit being configured to perform said measurement within the second passageway . a frame defining an enclosure, the frame extending between two end walls along a first axis and two lateral walls along a second axis, each of the two end walls being provided with an insertion aperture and each of the two lateral walls being provided with an insertion hole , the insertion apertures having a first dimension and the insertion holes having a second dimension for receiving therein elongated instruments having different cross-sectional sizes; a first hollow guiding structure extending between the two end walls within the frame and being aligned with the insertion apertures and defining a first passageway for receiving and guiding the elongated instrument inserted through one of the insertion apertures , and a second hollow guiding structure extending between the two lateral walls within the frame and being aligned with the insertion holes and defining a second passageway for receiving and guiding the elongated instrument inserted through one of the insertion holes , the two hollow guiding structures intersecting each other at an intersection zone; and a sensing unit contained within the frame and configured for measuring at least one of a displacement of the elongated instrument and a rotation of the elongated instrument, the sensing unit being positioned at the intersection zone for performing the measurement of the at least one of the displacement and the rotation at the intersection zone, the sensing unit being configured to perform said measurement within the first passageway and the sensing unit being configured to perform said measurement within the second passageway . <EOS>