Differential Diagnosis

  • Dorsal intercalated segmental instability
  • Scapholunate advanced collapse
  • Scapholunate dissociation
  • Volar intercalated segmental instability

27-year-old wrist Paid After A Fall XR Image with Resolution


This patient was diagnosed with scapholunate dissociation (disruption of the ligament between the scaphoid and lunate carpel bones), denoted by a widening of the scapholunate interval.  The patient also has rotation of the lunate and scaphoid.

Learnings/What to Look for

  • In adults, a scapholunate gap of >3 mm with clenched fist view (Terry Thomas sign) on AP radiographs is considered diagnostic of scapholunate dissociation
  • In children, the scapholunate interval is normally wider due to unossified portions of each of the carpal bones. Females have a shorter distance due to earlier skeletal maturity and reach adult values at ~11 years, whereas males reach adult values at ~12 years
  • The most common mechanism of injury is a fall on outstretched hand (FOOSH)

Pearls for Initial Management

  • Acute, nondisplaced and chronic asymptomatic scapholunate interosseous ligament injuries may be treated conservatively with nonsteroidal anti-inflammatories and immobilization
  • Surgical repair or reconstruction of the scapholunate interosseous ligament may be required to prevent long-term complications (eg, proximal migration of the capitate between the scaphoid and lunate, possibly resulting in scapholunate advanced collapse)

Acknowledgment: Image and case presented by Experity Teleradiology (www.experityhealth.com/teleradiology).

A 27-Year-Old Male with Pain After a Fall
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