Bone Plate System

A bone plate system comprising:

• a bone plate, an elongate bone anchor having a longitudinal axis, a locking cap, and a locking member, each being distinct components from each other;
• the bone plate having a plurality of throughbores with at least one of the throughbores having an annular surface extending thereabout;
• the locking cap having a pivotal wall disposed about and extending axially along a head portion of the bone anchor;
• the locking cap and locking member being arranged and mounted to the bone anchor head portion to allow the locking member to be shifted axially along the bone anchor head portion with the bone anchor, locking cap, and locking member received in the one throughbore to cause an upper portion of the pivotal wall to tightly engage the bone plate annular surface, and a lower portion of the pivotal wall to be urged into tight engagement with the bone anchor head portion.

A method of securing a bone plate to a bone, the method comprising:

• advancing a shank of a bone anchor assembly into a throughbore of the bone plate and into the bone, the bone anchor assembly including a bone anchor, a locking member, and a locking cap;
• locating an upper end portion of the bone anchor assembly including the locking member, the locking cap, and an upper rigid head portion of the bone anchor in the throughbore of the bone plate to be in an unlocked configuration therein;
• shifting the locking member of the bone anchor assembly along the rigid head portion of the bone anchor of the bone anchor assembly to cause the upper end portion of the bone anchor assembly to shift to a locked configuration in the throughbore;
• and
• expanding the locking cap of the bone anchor assembly mounted to the bone anchor head portion by the shifting of the locking member to cause the locking cap to tightly engage a bone plate surface extending about the throughbore for shifting the bone anchor assembly upper end to the locked configuration thereof.