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Carpometacarpal Joint Injection

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Other Names

  • CMC Joint Injection
  • Thumb CMC Joint Injection
  • CMCJ Injection
  • First carpometacarpal joint injection


Labeled radiograph PA radiograph of the wrist[1]

Key Points

  • This page refers to injection of the Carpometacarpal Joint of the thumb
  • This injection can be performed with or without ultrasound, although we recommend ultrasound
  • Use a 25 gauge, 1.5 inch needle
  • Transducer: high frequency linear array
  • Dorsal approach is optimal
  • Be careful to avoid the neurovascular bundle

Anatomy of the Carpometacarpal Joint

Palpation Guidance vs Ultrasound Guidance

  • Smith et al found palpation guided injections were 80% accurate while ultrasound guided injections were 100% accurate[2]
  • Derian et al, using a novel assessment scale, found no difference between ultrasound and palpation guidance in a cadaveric study[3]
  • Philip et al found palpation guidance had an accuracy of only 63%, that ultrasound improved accuracy but this was dependent on user experience[4]
  • Katt et al found palpation guidance to be only 80% accurate[5]



  • Absolute
    • Anaphylaxis to injectates
    • Overlying cellulitis, skin lesion or systemic infection
  • Relative
    • Can be treated with less invasive means
    • Hyperglycemia or poorly controlled diabetes
    • Lack of symptom improvement with previous injection


Demonstration of palpation guided injection[6]
Needle and probe position for in plane approach[7]
Ultrasound view for in-plane technique with needle (arow) trajectory.[7]
Needle and probe position for out of plane technique[7]
Ultrasound view for out of plane technique with needle (white dots) marking the trajectory[7]


  • Sterile including chloraprep, chlorhexadine, iodine
  • Gloves
  • Needle: typically 25 to 27 gauge, 0.5 to 1.0 inch
  • Syringe: 1-3 mL
  • Gauze
  • Ethyl Chloride
  • Bandage
  • Injectate
    • Local anesthetic
    • Corticosteroid

Ultrasound Findings

  • Use a high frequency, linear probe
  • Common findings:
    • Enlarged triangular joint space
    • Cortical irregularities
    • Erosions seen in inflammatory arthropathies
    • Effusion

Technique: Palpation Guided

  • Patient Position
    • The patient should be seated, alternatively they can be supine
    • Hand should be resting on the examination table
    • Radial side is up or superior, ulnar side resting on the table
  • Needle Orientation and Approach
    • Proximal to distal
  • Description
    • Palpate the small space between the trapezium and first metacarpal dorsally
    • Use the anatomic snuffbox for medial and lateral borders
    • Between the 1st and 2nd dorsal compartment
    • Mark this space with a pen or other blunt object
    • Sterilize the marked skin
    • Inject the needle into the joint space
    • Angle should be about 45° degrees to the skin
    • You should feel it "drop in" to the space
    • You may have to redirect cranial or caudal in small increments to achieve this
  • Pearls and Pitfalls
    • An assistant or the proceduralist should apply traction on the distal thumb to further open the joint space
    • Aspirate to make sure you aren't in a vessel prior to injection

Ultrasound Guided In-Plane

  • Patient position
    • Patient is seated or supine
    • Hand placed on table with ulnar sidse down, radial side up
  • Transducer position
    • Over the anatomic snuff box
    • Aligned with the long axis of the carpometacarpal joint
  • Needle Orientation and Approach
    • In Plane
    • Stand off oblique technique
  • Target
    • CMC joint space
  • Pearls and Pitfalls
    • Be careful to avoid the neurovascular bundle
    • Joint space is characterized by the "seagull" appearance of the carpal and metacarpal reflection

Ultrasound Guided Out-of-Plane

  • Patient position
    • Patient is seated or supine
    • Hand placed on table with ulnar sidse down, radial side up
  • Transducer position
    • Over the anatomic snuff box
    • Aligned with the long axis of the carpometacarpal joint
  • Needle Orientation and Approach
    • Out of Plane
    • Step-wise technique
  • Target
    • CMC joint space
  • Pearls and Pitfalls
    • See above


  • No significant restrictions
  • Can augment with ice, NSAIDS
  • Consider placement in a Thumb Spica Splint


  • Skin: Subcutaneus fat atrophy, skin atrophy, skin depigmentation
  • Painful local reaction
  • Infection
  • Hyperglycmia
  • Tendon, nerve or blood vessel injury

See Also


  1. Vos, F. M., et al. "A statistical shape model without using landmarks." Proceedings of the 17th International Conference on Pattern Recognition, 2004. ICPR 2004.. Vol. 3. IEEE, 2004.
  2. Smith, Jay, et al. "Accuracy of sonographically guided and palpation guided scaphotrapeziotrapezoid joint injections." Journal of Ultrasound in Medicine 30.11 (2011): 1509-1515.
  3. Derian, Armen, et al. "Accuracy of ultrasound-guided versus palpation-based carpometacarpal joint injections: a randomized pilot study in cadavers." Ultrasound 26.4 (2018): 245-250.
  4. To, Philip, et al. "The accuracy of common hand injections with and without ultrasound: an anatomical study." Hand 12.6 (2017): 591-596.
  5. Katt, Brian M., et al. "The efficacy of intra-articular versus extra-articular corticosteroid injections in the thumb carpometacarpal joint." Journal of Hand Surgery Global Online 4.3 (2022): 128-134.
  6. Image courtesy of rheumatologynework.com, "injection of first carpometacarpal joint"
  7. 7.0 7.1 7.2 7.3 Malanga, Gerard, and Kenneth Mautner. Atlas of ultrasound-guided musculoskeletal injections. McGraw-Hill, 2014.
Created by:
John Kiel on 18 October 2022 17:00:51
Last edited:
10 January 2024 16:13:38