the second surface 6 measured in the central plane 11 the first central axis 17 and the second central axis 19 of the additional compound opening form an angle u03b3 the intramedullary nail aiming device 1 may further comprises an aiming arm 9 which may be attached to the proximal end of the intramedullary nail 8 the aiming arm 9 has a first end 20 including a first joining mechanism 24 and a second end 21 including a second joining mechanism 25 the first joining mechanism 24 of the aiming arm 9 may be coupled to a third joining mechanism of the aiming plate 2 the first joining mechanism 24 comprises two pins 45 axes of which lie in the central plane 11 and are spaced apart from one another the third joining mechanism 26 may include bores 46 at a proximal end 7 of the aiming plate 2 for receiving the pins 45 of the first joining mechanism 24 therethrough further the first joining mechanism 24 includes a screw 47 penetrating a respective hole not shown in the aiming plate 2 to releasably couple the aiming plate 2 to the aiming arm 9 the second joining mechanism 25 of the aiming arm 9 comprises two further pins 49 and a fastener 48 for releasably coupling the aiming arm 9 to the intramedullary nail 8 the intramedullary nail 8 comprises a fourth joining mechanism 27 including for example two lateral holes and a coaxial hole engageable with the second joining mechanism 25 of the aiming arm 9 to allow the releasable coupling of the aiming arm 9 to the intramedullary nail 8 in an aligned position as illustrated in fig2 if a drill bushing 4.