A 24-year-old man sustained a transverse fracture of the waist of the scaphoid six months ago, treated conservatively. He now has persistent wrist pain. MRI shows collapse and sclerosis confined to the proximal fragment. The blood supply to this fragment is compromised because it is supplied by:

• A Branches entering the tubercle from the superficial palmar arch
• B Anastomosis with the lunate through the radioscapholunate ligament
• C The anterior interosseous artery entering the dorsal ridge
• D Retrograde vessels entering the distal pole from the radial artery ✓

Explanation

The scaphoid is supplied by branches of the radial artery that enter predominantly through the distal pole and dorsal ridge, so flow to the proximal pole is retrograde. A waist fracture interrupts this retrograde supply and predisposes the proximal fragment to avascular necrosis and non-union. This explains why displaced proximal pole fractures are treated operatively even when nondisplaced.

Reference: Gray's Anatomy, 42nd ed.

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Written and medically reviewed by the StethoPrep medical team.