The Wrist

Authored by Dr. Javier Andrade

• With any orthopedic injury, it is important to understand the normal bony anatomy of the injured area you are examining:
  • The Wrist is a complex area with multiples bones and joint.
  • It is composed of the more proximal ulna and radius which anchor the wrist and help create the supination and pronation needed for complex hand movements
  • The distal portion of the wrist is made up of the 8 carpal bones arranged in two rows.

• Now that we now what bones make up the wrist, we can talk a bit more about the alignment and tricks we can use to see if there is an injury to the wrist.
  • One such trick we can use for the PA view are Gilula’s Line. It is a technique which uses 3 curved lines to check the alignment of the carpal bone rows.
    • Proximal row, proximal portion (pink)
    • Proximal row, distal portion (blue)
    • Distal row, proximal portion (red)

• Also, as with any ortho injury, remember to assess that the patient is neurovascularly intact!
  • Vascular: Can use the doppler probe to assess
    • Ulnar artery
    • Radial Artery
    • Palmar arch
  • Nerves:
    • Radial n: Test the extensor pollicus longus using “thumbs up”
    • Median n: Test using the “OK sign”
      • Make sure patient flexes at the DIP joint
    • Ulnar n: Test using pinky abduction
• Pathology:
  • Scaphoid Fx
    • Most commonly injured carpal bone and can be easily missed. If you have clinical exam findings but no radiologic findings, treat this as a fracture!
    • Tx: Thumb spica cast and reimage in 12 days.
  • Lunate and Perilunate dislocation
    • Associated with high-energy mechanism of injury as it has to tear through multiple ligaments that hold the hand together. Be on the lookout for other injuries in the wrist.
      • Associated with median n injury in 25% of patients
    • Notice the anatomy on the normal image (left). We can use the lines on the lateral XR view to assess for injury

• Hamate fracture:
  • Body: Clenched fist against solid object
    • Typically requires surgical intervention
  • Hook: Associated with injuries that require swinging equipment (baseball, tennis, etc.)
    • Can cause ulnar n. injury or impingement
• Distal Radius Fractures:
  • Colle’s: Fx with posterior displacement
  • Smith’s: Fx with anterior displacement
• Distal Radial-Ulnar joint (DRUJ) injuries
  • Normally, the ulna sits on a small groove on the distal radius known as the sigmoid notch.
    • Any spacing here is abnormal

• Management:
  • If purely ligamentous closed immobilization and outpatient follow-up
  • If associated with fracture then operative repair is necessary