The present invention relates to a plunger rod (1) for an injection device, comprising a distal element (20) slidingly coupled to a proximal element (30) having one radially flexible branch (33),- locking means (23, 33, 35) for selectively locking the distal element and the proximal element in a plurality of relative axial positions defining a plurality of intermediate positions of the plunger rod,wherein the locking means is movable from a locked state, in which the distal element and the proximal element are fixed with respect to each other in the axial direction, and an unlocked state, in which the distal element and the proximal element are displaceable in the axial direction with respect to each other, when the radially flexible branch is displaced radially. The invention also relates to an injection device comprising such a plunger rod.
