A bone anchor (1, 101, 201), comprising:a main body defining a longitudinal axis (26) and comprising: a head (6, 106, 206) anda shank (2)at least one longitudinal recess (3, 103, 203) having a first end formed at the head (6, 106, 206) and a second end fanned at the shank (2), the recess (3, 103, 203) extending from the first end through a portion of the head (6, 106, 206) and along a portion of the shank (2) to the second end, wherein the recess (3, 103, 203) is configured to receive therein a pin-shaped element (4, 104, 204)a stop (36) being provided at the second end of the recess (3, 103, 203), said stop (36) being configured to engage or abut a distal end portion (43) of the pin-shaped element (4, 104, 204)a locking structure (5, 105, 205) being provided adjacent the first end of the recess (3, 103, 203), said locking structure (5, 105, 205) being configured to engage and exert a biasing force on a proximal end portion (42, 142, 242) of the pin-shaped element (4, 104, 204) towards the stop (36) such as to stress and bend an intermediate portion (44) of the pin-shaped element (4, 104, 204) in a transverse direction (E) away from the shank (2).
