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.