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Arthrocentesis of the Glenohumeral Joint


Calvin Eric Hwang, MD CAQ-SM
Clinical Assistant Professor
Department of Orthopaedic Surgery
Stanford University School of Medicine


  • Glenohumeral (GH) joint aspiration and injection is a useful procedure in the ED to rule out septic arthritis and diagnose crystal arthropathies.
  • Glenohumeral joint steroid injection can be considered in patients with suspected adhesive capsulitis.
  • Glenohumeral joint procedures should be performed under ultrasound guidance
Standard probe position for a glenohumeral arthrocentesis or injection. [1]Image courtesy of, “Arthrocentesis: Shoulder”
Video demonstrating arthrocentesis. The curvilinear probe is posterior over the shoulder. The needle is in plane and can be seen in the hypoechoic fluid within the capsule actively aspirating.


  • The GH joint is frequently injured and is a common cause for presentation to the Emergency Department (ED).
  • Septic arthritis in the shoulder is uncommon, but can present atypically so a high index of suspicion is necessary when evaluating someone with fever, shoulder pain, and limited range of motion.
  • US guided shoulder arthrocentesis can be performed by emergency physicians to diagnose septic arthritis and crystal arthropathies.[2]Nagdev A. Ultrasound-Guided Glenohumeral Joint Evaluation and Aspiration. ACEP Now. 2016;35(6).
  • Conversely, US guided GH steroid injections can be considered in patients presenting with suspected adhesive capsulitis.


  • The shoulder girdle is composed of the proximal humerus, scapula and clavicle.
  • The primary joint of the shoulder is the glenohumeral joint and would be the primary target for arthrocentesis to rule out septic arthritis.
  • Movement about the glenohumeral joint is from the rotator cuff muscle group, deltoid, and biceps brachii muscles.
Anatomy of the glenohumeral joint.[3]Varacallo M, El Bitar Y, Mair SD. Figure, Shoulder Joint Anatomy. Contributed By. StatPearls Publishing; 2021. (click to enlarge)

Ultrasound Evaluation

  • A linear or curvilinear probe, depending on body habitus, should be used for evaluation of the glenohumeral joint.
  • The patient should be in the seated or lateral decubitus position with the affected shoulder up and the affected arm across the patient’s chest.
  • The ultrasound probe should be placed in plane with and just inferior to the lateral aspect of the scapula spine. With this approach, the humeral head, glenoid rim, labrum and infraspinatus muscle should be visualized.
Demonstration of patient laying in the lateral decubitus position with the linear probe. The glenohumeral joint is easily seen (*), as is the humerus (H), glenoid (GP), infraspinatus (IS) and deltoid.[4]Image courtesy of, “How I Do It: Ultrasound-Guided Injection for the Shoulder (Part 2)”
  • Shoulder joint effusions are best visualized in the posterior recess of the glenohumeral joint. An effusion, if present, will be readily visible as an anechoic collection deep to the infraspinatus and contained within the joint capsule.
  • This potential space would also be the target for an injection. Imaging of the contralateral side can be performed for comparison.
Ultrasound showing normal glenohumeral joint with the curvilinear probe.
Ultrasound showing effusion of the glenohumeral joint.


  • Landmark vs. Ultrasound Guided Approach
    • Both landmark and ultrasound-guided approaches to glenohumeral and acromioclavicular joint arthrocentesis have been described.
    • For the glenohumeral joint, studies have shown that ultrasound-guided approaches are 92-100% accurate while success rates with landmark-based approaches are only 27-73%.[5]Baxi N, Spinner DA. Shoulder. In: Spinner DA, Kirschner JS, Herrera JE, eds. Atlas of Ultrasound Guided Musculoskeletal Injections. Vol 2014. Springer; :7–16.
    • Although landmark-guided aspirations have been shown to be faster (52 seconds vs 166 seconds), the increased accuracy of ultrasound guidance would seem to outweigh the speed benefit.[6]Patel DN, Nayyar S, Hasan S, Khatib O, Sidash S, Jazrawi LM. Comparison of ultrasound-guided versus blind glenohumeral injections: a cadaveric study. J Shoulder Elbow Surg. 2012;21(12):1664-1668.
    • Note that the landmark or palpation based approach was studied in orthopedic surgeons who presumably perform the procedure more often and thus have increased skill with this approach.
    • For this reason, we strongly encourage emergency medicine physicians to utilize ultrasound when performing procedures involving the glenohumeral joint.
  • Materials
    • 18 gauge draw needle
    • 1.5 inch, 25 gauge needle for local anesthetic administration
    • 1.5 to 3.5 inch, 18 – 23 gauge needle for aspiration
    • 5 – 10 cc syringe
    • Local anesthetic
    • Sterile equipment (gauze, skin prep, gloves, probe cover, etc)

Palpation Guided Technique

  • General
    • Can be performed without assistance
    • Procedure should be done with strict sterile technique
  • Position
    • Patient should be in seated position
    • Alternatively, the patient can lay in the lateral decubitus position with the affected arm up.
  • Anterior approach
    • Identify humeral head, distal clavicle and coracoid.
    • Insert needle medial to the humeral head and inferolateral to the coracoid.
  • Posterior approach
    • Identify the posterolateral border of the acromion.
    • Insert needle approximately 2 cm inferior to the posterolateral border of the acromion.
    • Direct needle anteromedially towards the coracoid process.
Status post injection using the anterior approach.[7]Ağırman M, Leblebicier MA, Durmuş O, Saral İ, Gündüz OH. Should we continue to administer blind shoulder injections? Eklem Hastalik Cerrahisi. 2016;27(1):29-33.
Demonstration of the posterior approach.[8]Image courtesy of, “Shoulder Joint Injection”

Ultrasound Guided Technique

  • General
    • Can be performed without assistance
    • Procedure should be done with strict sterile technique.
  • Patient Position
    • Patient should be in the seated or lateral decubitus position with the affected side up and the affected arm relaxed across the body
  • Ultrasound
    • Place the probe parallel and just inferior to the lateral aspect of the scapula spine and identify the humeral head, glenoid rim, labrum and infraspinatus muscle.
Standard position to ultrasound the glenohumeral joint
Standard probe position for a glenohumeral arthrocentesis or injection. Note the patient can be upright or in the lateral decubitus position.[9]Image courtesy of, “Arthrocentesis: Shoulder”
    • Synovial fluid will appear as an anechoic collection in the posterior joint recess deep to the infraspinatus
  • Local anesthetic should be injected into the soft tissue
    • Performed in plane, with needle vector along anticipated approach to joint space
  • Under ultrasound guidance
    • A spinal needle should be inserted with direct visualization in the long axis into the hypoechoic collection. 
    • The needle can be inserted either medial-to-lateral or lateral-to-medial. 
    • Apply doppler to evaluate for the presence of and to avoid any vessels. 
    • Negative pressure with the syringe should be maintained throughout. 
  • Aspirate until all visible fluid has been collected. 
    • Fluid may be sent for gram stain, culture and fluid/crystal analysis
  • Injection can be performed using the same approach
Demonstration of needle guidance into the glenohumeral joint.
Demonstration of internal and external rotation of the glenohumeral joint to confirm anatomy.
Ultrasound guided injection with capsular distension for adhesive capsulitis. Note the same view would be seen if performing an arthrocentesis.
UIltrasound guided glenohumeral injection. Note this is the posterior approach and the needle is out of plane with the probe, but still visualized.

Additional Considerations

  • Benefits
    • Easy to visualize effusion.
    • Procedure is performed with direct needle visualization throughout
    • Arthrocentesis and injection can each be both diagnostic and therapeutic.
    • Can speed time to diagnosis and disposition.
    • If uncertain about glenohumeral joint location on ultrasound, gently internally and externally rotate the arm to find the mobile humeral head moving within the fixed glenoid rim.

Pearls & Pitfalls

  • A 1.5 inch, 22 gauge or larger spinal needle should be used for glenohumeral joint aspiration/injection. The flexibility of thinner needles makes the procedure more difficult to perform.
  • If indicated, medication (e.g. steroid or anesthetic) can be injected into the glenohumeral or acromioclavicular joint using the same approach.