The parts of a surgical instrument, explained in detail

The basic layout: rings, shanks, joint and jaws

A ring-handled instrument is built as two halves that cross at a joint. The finger rings at one end are where the hand holds the instrument. The shanks run from the rings to the joint, and beyond the joint the jaws or blades form the working end.

This lever arrangement multiplies the force of the hand at the tip. The longer the shanks relative to the jaws, the more leverage, which is why deeper instruments are usually longer overall.

The same anatomy applies to haemostatic forceps, needle holders and many scissors, which is why the vocabulary carries from one instrument to another.

The joint: box lock and screw lock

Most modern instruments use a box lock, in which one half passes through a slot in the other, forming a strong, flat joint that does not loosen easily. Scissors often use a screw lock with an adjustable pivot screw, which allows blade tension to be set and serviced.

Check the joint for smooth motion without side play. A joint that is loose or gritty usually points to wear or poor machining. Cleaning the box lock thoroughly is essential, since debris collects in the recess.

If a joint is stiff when new, it may need only light lubrication with an approved instrument milk, but stiffness that persists is a reason to reject the item.

The ratchet and the jaws

The ratchet is a toothed locking mechanism on the shanks that keeps the instrument closed at a set tension. It is found on haemostats and needle holders. The teeth should engage cleanly and release with a small outward movement of the hand, without slipping under load.

Jaw design depends on the job. Haemostats have serrations along the jaws to grip vessels; needle holders have short, strong jaws with cross-hatching or tungsten carbide inserts to hold a needle; scissors have blades that must meet along their length. See haemostatic forceps and needle holder types for pattern details.

REDA's forceps and clamps and needle holders are listed in several lengths, including TC versions of many needle holder patterns.

• Rings: hold the instrument and set comfort and control
• Shanks: transmit force and define reach
• Box lock or screw: connects the halves
• Ratchet: holds closure
• Jaws and tips: do the work

What to inspect on receipt

Close the instrument fully and look along the jaws: they should meet at the tips and along the length without gaps. Check serrations for alignment and for burrs, and check that the rings are smooth and free from sharp edges.

For scissors, test the cut on thin material and check that the blades do not catch or squeak. Our quality grades guide explains how finish and machining indicate quality.

Terms worth knowing when you talk to a supplier

Use the correct names to avoid misunderstandings. The tips are sometimes called points, the serrated inner surface of the jaws is the gripping area, and the hinge is also called the joint or lock. For scissors, the cutting edges are blades, and the screw or box that joins them is the pivot.

When you report a fault, say which part is affected: for example a ratchet that does not hold, a joint that is loose, or jaws that do not meet at the tip. This makes it much easier for a supplier or service centre to quote and repair correctly.

Photographs of the fault, together with the catalogue reference, speed up the process further.

Maintenance, wear and service

With use, jaws wear, ratchet teeth round off and joints loosen. Regular inspection catches these faults early and allows repair before a failure during a procedure. See instrument repair and sharpening for service intervals.

Where TC inserts are used, check that they are firmly seated and that no cracks or chips appear, and read about the benefits in tungsten carbide surgical instruments.

Beckfinity can provide REDA instruments with product documentation and help your team compare options. Contact our specialists to request a quotation.