Lateral plate and spinal implant system and method

A plate assembly comprising:

• an elongated plate for attachment to adjacent vertebrae, the elongated plate having a first end portion and a second end portion, the first end portion comprising a first aperture for receiving a first bone screw, the second end portion comprising a second aperture for receiving a second bone screw, and wherein the position of the first aperture and the position of the second aperture are fixed along the elongated plate;
• a moveable element with an opening in communication with the second aperture, wherein the moveable element is configured to move along the length of the second end portion to adjust the distance between a head of the first bone screw and a head of the second bone screw;
• a threaded third aperture interposed between the first aperture and the second aperture;
• and
• an anti-back out mechanism assembly having a locking tab, an externally threaded screw, and a locking ring, wherein the externally threaded screw is configured to engage with an aperture of the locking tab and the threaded third aperture, wherein the locking tab projects over at least a portion of the head of the first bone screw and over at least a portion of the head of the second bone screw.