Variable angle bone plate

A bone fixation system comprising:

• a bone plate that defines an inner surface configured to face bone and an outer surface opposite the inner surface along an axially outward direction, the bone plate including:
• (a) an internal surface defining a fixation hole that extends from the outer surface to the inner surface along a central hole axis oriented along a transverse direction;
• and
• (b) at least one thread that extends from the internal surface into the fixation hole,
• wherein the bone plate further defines a plurality of recesses that extend along a radial direction away from the central hole axis
• and divide the at least one thread into a plurality of columns of thread segments offset from each other along the transverse direction, such that the thread segments of each of the columns are consecutive with each other and have respective circumferential lengths that sequentially increase in an axially inward direction that is opposite the axially outward direction, and
• a bone anchor having a threaded head and a shaft that extends out with respect to the threaded head, wherein the threaded head is configured to threadedly mate with the at least one thread selectively when the bone anchor is oriented at first and second different orientations with respect to the central hole axis.