A retractor blade assembly mounted on a blade post , the retractor blade assembly comprising: a blade holder attached to the blade post , and which pitches relative to the blade post; a first locking mechanism configured to arrest pitch of the blade holder relative to the blade post ; a retractor blade rotatably engaged to the blade holder to allow the blade to yaw relative to the blade holder ; and a second locking mechanism configured to arrest yaw of the retractor blade relative to the blade holder independent of the first locking mechanism ; characterized in that the first locking mechanism is formed by the blade post being split into two post arms terminating in a pair of parallel disc members , each disc member containing a central aperture, and each disc member having a scalloped surface facing the other disc member ; and the blade holder comprising: a compression body between the pair of disc members , having a second central aperture and having at least two surfaces each proximate to one of the pair of disc members , the at least two surfaces having scalloped textures that interlock with the scalloped surfaces on the disc members ; and an axle running through the apertures on the disc members and the second aperture in the compression body ; and a locking mechanism reversibly pinching the pair of disc members against the compression body to arrest pitch of the blade holder relative to the blade post . a blade holder attached to the blade post , and which pitches relative to the blade post; a first locking mechanism configured to arrest pitch of the blade holder relative to the blade post ; a retractor blade rotatably engaged to the blade holder to allow the blade to yaw relative to the blade holder ; and a second locking mechanism configured to arrest yaw of the retractor blade relative to the blade holder independent of the first locking mechanism ; characterized in that the first locking mechanism is formed by the blade post being split into two post arms terminating in a pair of parallel disc members , each disc member containing a central aperture, and each disc member having a scalloped surface facing the other disc member ; and the blade holder comprising: a compression body between the pair of disc members , having a second central aperture and having at least two surfaces each proximate to one of the pair of disc members , the at least two surfaces having scalloped textures that interlock with the scalloped surfaces on the disc members ; and an axle running through the apertures on the disc members and the second aperture in the compression body ; and a locking mechanism reversibly pinching the pair of disc members against the compression body to arrest pitch of the blade holder relative to the blade post . a compression body between the pair of disc members , having a second central aperture and having at least two surfaces each proximate to one of the pair of disc members , the at least two surfaces having scalloped textures that interlock with the scalloped surfaces on the disc members ; and an axle running through the apertures on the disc members and the second aperture in the compression body ; and a locking mechanism reversibly pinching the pair of disc members against the compression body to arrest pitch of the blade holder relative to the blade post . <EOS>