Anatomy of the wrist
Let's start by reviewing the anatomy of the wrist joint.
The wrist joint is found between the distal end of the radius and ulna, and the first row of carpal bones.
When tapping a wrist, it is important that you insert the needle on the ulnar side of the extensor pollicis longus tendon to avoid injury to the radial artery and nerve. To help you identify the tendon, have your patient give you a thumbs-ups!
Ideal positioning for arthrocentesis of the wrist
Now that you’ve identified the tendon, it’s time to properly position your patient for a wrist tap:
- Patient’s affected arm is resting on a table or stretcher
- Forearm is pronated (palm facing down)
- Wrist is flexed 25° downwards
- Wrist is rotated away from the thumb (ulnar deviation)
Once the patient is positioned, you will stand in front of the affected wrist to perform the arthrocentesis procedure on the wrist joint.
How to perform arthrocentesis of the wrist
The arthrocentesis procedure requires five simple steps to ensure a safe, clean, and painless wrist tap:
- Direct a 22 gauge (G) needle at the end of the radius on the ulnar side of the extensor pollicis longus tendon.
- Aspirate as soon as your needle enters the skin.
- Stop advancing the needle when you see fluid.
- Extract the joint fluid.
- Take the needle out and apply a bandage.
Excellent work! You now know the basic procedure for a wrist arthrocentesis.
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- Roberts, J. 2019. “Arthrocentesis”. In: Roberts and Hedges’ Clinical Procedures in Emergency Medicine and Acute Care. 7th edition. Philadelphia: Elsevier.