Polyaxial bone plate and locking assembly

A locking bone plate apparatus, comprising:

• a bone plate and a plurality of rotatable locks, wherein:
• the bone plate comprises a plurality of screw through-holes and a plurality of bores that extend into a superior surface of the bone plate along respective longitudinal axes, the plurality of screw through-holes arranged in sets that are each positioned proximate to one of the plurality of bores, each bore of the plurality of bores comprising a flexible locking device positioned in the bore, each flexible locking device having a curved inner surface and a c-shaped curvature that defines a partial arc around the respective longitudinal axis of the bore when the flexible locking device is not flexed;
• and
• each rotatable lock of the plurality of rotatable locks comprises an elongated head portion and a shaft configured to be received in one of the plurality of bores, each shaft comprising a respective radial feature configured to interact with the flexible locking device of the one of the plurality of bores when the shaft is received in the one of the plurality of bores, wherein:
• when one of the plurality of rotatable locks is received in one of the plurality of bores of the bone plate, the one of the plurality of rotatable locks is configured to rotate between an unlocked position and a locked position;
• in the unlocked position, the elongated head portion does not obstruct a screw backout path of an adjacent screw through-hole of the plurality of screw through-holes;
• in the locked position, the elongated head portion obstructs the screw backout path of the adjacent screw through-hole;
• and
• the radial feature of the one of the plurality of rotatable locks is configured to interact with the flexible locking device to cause the rotatable lock to resist rotation away from the unlocked position or away from the locked position.

A method of securing a bone plate in a bone plate assembly comprising a bone plate and a rotatable lock, the bone plate comprising a screw through-hole, a bore that extends into a superior surface of the bone plate along a longitudinal axis, the bore configured to receive the rotatable lock, and a flexible locking device positioned in the bore having a c-shaped curvature that defines a partial arc around the longitudinal axis of the locking bore when the flexible locking device is not flexed, and the rotatable lock comprising an elongated head portion, a shaft that extends into the bore, and a radial feature from the shaft, the method comprising:

• rotating the rotatable lock within the bore from an unlocked position to a locked position, wherein:
• in the unlocked position, the radial feature is received in a first depression of the flexible locking device, the elongated head portion is positioned to not obstruct a backout path above the screw through-hole, and the radial feature interacts with the flexible locking device to cause the rotatable lock to resist rotation away from the unlocked position;
• and
• in the locked position, the radial feature is received in a second depression of the flexible locking device separated from the first depression, the elongated head portion is positioned to obstruct the backout path, and the radial feature interacts with the flexible locking device to cause the rotatable lock to resist rotation away from the locked position.