Which statement best describes the arterial supply of the scaphoid that explains the high rate of nonunion and avascular necrosis after proximal pole fractures?

• A Dual supply from both the radial and ulnar arteries at the waist
• B Antegrade flow enters through vessels at the proximal pole from the anterior interosseous artery
• C Retrograde flow enters through vessels along the dorsal ridge at the distal pole ✓
• D Supply entirely from branches of the deep palmar arch at the tuberosity

Explanation

The scaphoid is supplied mainly by the dorsal scaphoid branch of the radial artery, which enters the distal pole and dorsal ridge, supplemented by volar branches entering the tuberosity. Flow is therefore retrograde, running from distal to proximal. C fracture through the waist or proximal pole disrupts this retrograde supply to the proximal fragment, producing nonunion and avascular necrosis of the proximal pole.

Reference: Miller's Review of Orthopaedics, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.