How to perform arthrocentesis of the shoulder

Siamak Moayedi, MD
19th Nov 2020

Anatomy of the shoulder

The shoulder joint is found between the humerus and the glenoid fossa of the scapula. The easiest way to get to the shoulder joint for arthrocentesis is to use an anterior approach. So you will need to landmark the coracoid process which feels like a hard bump just inferior to the acromioclavicular (AC) joint and in front of the humerus.

Anatomy of a shoulder: Front view of shoulder with labels on the acromioclavicular (AC) joint, coracoid process, and humerus. Illustration.

Figure 1.  Anatomy of a shoulder. 

 

Ideal positioning for arthrocentesis of the shoulder

For a shoulder arthrocentesis, or shoulder tap, you need to properly position your patient: 

  • The patient is sitting down
  • Their hand (of the affected arm) is in their lap 

Image of the torso and upper extremities of a seated patient with right arm resting in their lap. Cartoon.

Figure 2. Ideal positioning for arthrocentesis of the shoulder. The patient is sitting down with their affected arm in their lap. 

Once the patient is positioned, you will stand in front of them to perform the arthrocentesis procedure on the affected shoulder joint. 

 

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How to perform arthrocentesis of the shoulder

The arthrocentesis procedure requires six simple steps to ensure a safe, clean, and painless shoulder tap: 

  1. Direct your 20 gauge (G) needle just below and lateral to the coracoid process.
  2. Keep the needle parallel to the floor. 
  3. Aspirate as soon as your needle enters the skin.
  4. Advance the needle until you get fluid into your syringe. 
  5. Extract the joint fluid.
  6. Take the needle out and apply a bandage. 

Key points for performing arthrocentesis for the shoulder: Anterior view of shoulder joint with bones shown. Icons for 20 gauge needle, arrow. Cartoon.

Figure 3. How to perform arthrocentesis for the shoulder. 1) Insert your 20 gauge (G) needle just below and lateral to the coracoid process. 2) Keep your needle parallel to the floor throughout the procedure. 3) Aspirate as soon as your needle enters the skin. 4) Advance until fluid fills the syringe. 5) Extract the joint fluid. 6) Take the needle out, and apply a bandage. 

Congratulations, you have now covered the basics for how to complete a shoulder arthrocentesis! 

 

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Recommended reading

  • Roberts, J. 2019. “Arthrocentesis”. In: Roberts and Hedges’ Clinical Procedures in Emergency Medicine and Acute Care. 7th edition. Philadelphia: Elsevier.