Bone anchors with drag features

Bone anchors are disclosed herein. In some embodiments, a bone anchor can include a drag interface. Exemplary drag interfaces include (i) friction between a shank and a bushing, (ii) friction between a bushing and a drag ring, (iii) friction generated by a biased saddle, and (iv) combinations of the above. The drag interface can help maintain the relative position between a receiver member and a shank of the bone anchor prior to locking the bone anchor, preventing unintended movement while still allowing free movement when intended by the user. In some embodiments, a bone anchor can include over-rotation blocking features, such as a groove, lip, or protrusion formed on a bushing of the bone anchor. Various other bone anchor features are also disclosed, including high aspect ratio drag rings and compressible drag posts.