Certified Surgical Technologist (CST) Practice Exam

Which of the following is the correct sequence of instruments for placing a screw into bone?

1. Depth gauge, Drill, Screw driver, Tap

2. Drill, Screw driver, Depth gauge, Tap

3. Screw driver, Tap, Depth gauge, Drill

4. Drill, Tap, Screw driver, Depth gauge

The correct answer is: Depth gauge, Drill, Screw driver, Tap

The sequence of instruments for placing a screw into bone begins with the depth gauge, which is used to measure the appropriate depth of the screw hole before drilling. This is crucial for ensuring that the screw is set at the correct depth within the bone structure. After using the depth gauge, the next instrument is the drill, which creates the actual hole in the bone. The drill must be appropriately sized for the screw being used, as this directly affects the stability of the fixation. Once the drill has done its job, the screw driver is employed to insert the screw into the drilled hole. It is important to use the screw driver correctly to ensure the screw is driven in straight and tightens securely. After inserting the screw, the tap is used to create threads in the bone, which can be necessary if the bone is particularly hard or if greater screw retention is required. Utilizing the tap after placing the screw is less common in many procedures; instead, it is often done prior to screw insertion to prepare the bone for better engagement of the screw. In summary, this sequence of using a depth gauge, followed by drilling, then using a screw driver, and finally tapping ensures a proper and secure fixation when placing a screw into bone, making option A the appropriate