Asseion - Distal pole of scaphoid goes to avascular necrosis after scaphoid fracture.Reason- Blood supply of scaphoid is from distal to proximal.
(A) Asseion is true but reason is false (B) Both asseion reason are true and reason explains asseion (C) Both asseion and reason are false (D) Reason is true but asseion is false
(D) Ans. D. Reason is true but asseion is falseThe main blood supply to the scaphoid enters through the non-aicular dorsal ridge at the waist of the bone and the volar tubercle at the distal aspect of the bone.A dorsal branch of the radial aery accounts for 80% of the blood supply of the scaphoid.A separate volar aerial branch to the scaphoid enters the tubercle and accounts for 20-30% of the scaphoid's blood supply, mainly to the distal poion.The proximal pole of the scaphoid relies entirely on intramedullary blood flow.The unusual retrograde nature of the scaphoid's blood supply renders it especially prone to non-union and proximal pole avascular necrosis