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 and a second end formed at the shank, the recess extending from the first end through a portion of the head and along a portion of the shank to the second end, wherein the recess is configured to receive therein a pin-shaped element (4, 104, 204)a stop (36) being provided at the second end of the recess, said stop being configured to engage or abut a distal end portion (43) of the pin-shaped elementa locking structure (5, 105, 205) being provided adjacent the first end of the recess, said locking structure being configured to engage and exert a biasing force on a proximal end portion (42, 142, 242) of the pin-shaped element towards the stop such as to stress and bend an intermediate portion (44) of the pin-shaped element in a transverse direction (E) away from the shank.
