Bone anchor

An anchor assembly couplable to bone, the assembly comprising:

• an anchor comprising:
• a shank securable to bone;
• and
• a head coupled to a proximal portion of the shank;
• and
• a housing comprising:
• a proximal portion including an anchor bore extending distally into the housing along a longitudinal axis of the housing, the anchor bore configured to retain the head of the anchor therein;
• and
• a distal portion including a secondary bore configured to engage the anchor to limit angulation of the anchor relative to the housing, the secondary bore comprising:
• a first portion configured to limit the angulation of the anchor to a first angle relative to the longitudinal axis;
• and
• a plurality of second portions each configured to limit the angulation of the anchor to a second angle relative to the longitudinal axis that is greater than the first angle;
• wherein one of:
• the secondary bore has a geometric shape substantially of a square with rounded corners from a distal perspective;
• and
• the first portion is defined by a first chamfer extending radially outward from the secondary bore, wherein each of the plurality of second portions are defined by a plurality of bevels extending radially outward, and wherein each of the plurality of bevels curves along a face of each of the plurality of bevels.