Abstract: An apparatus is provided for securing a surgical instrument at a predetermined attitude and at a predetermined location about an operating table. The apparatus includes instrument gripping means pivotally mounted upon a flexible column, which in turn is pivotally mounted upon locking means configured to slide about an operating table positioning bar. Tensioning means are provided in operative communication with the instrument gripping means, the flexible column and the locking means. Upon actuation of the tensioning means, the instrument gripping means securely grasps a surgical instrument at a predetermined attitude relative the operating table, the flexible column rigidifies in a predetermined posture and the locking means become non-movable relative the positioning bar.