a retaining device for fixedly holding a surgical instrument in a predetermined spatial orientation during surgery comprising an arm having a ball - and - socket joint for grasping the surgical instrument , another arm having a ball - and - socket joint for securing the device to a stationary base and an intermediate pin joint which connects the arms and acts in conjunction with the ball - and - socket joints to allow placement of the surgical instrument in a desired position . the retaining device further comprised a means at the pin joint for simultaneously tightening all joints of the device after placement of the surgical instrument and thereby fixing the position of the surgical instrument .