QuestionSBA
QuestionChoice
The lunate is supplied by the branches of the deep palmar arch between the radial and ulnar arteries. Although it can undergo avascular necrosis (Kienbock's disease), proximal avascular necrosis of the lunate bone is not associated with a fall on the outstretched hand.
10000998
c
Lunate
QuestionChoice
The pisiform is supplied by the dorsal carpal, lateral pedicle and lower pedical branches of the ulnar artery. Pisiform fractures are typically associated with direct trauma, however, avascular necrosis is very rare.

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10001000
e
Pisiform
QuestionChoice
The hamate is supplied by the branches of the deep palmar arch between the radial and ulnar arteries. Although the hook of the hamate is at risk of avascular necrosis after fracture, the proximal aspect of the hamate is not.
10000997
b
Hamate
QuestionChoice
The trapezoid is supplied by numerous branches of the deep palmar arch between the radial and ulnar arteries. Avascular necrosis of the trapezoid is rare and is known to spontaneously resolve.
10000999
d
Trapezoid
QuestionChoice
The scaphoid bone has a retrograde arterial supply from the radial artery as it passes through the anatomical snuffbox, around the thumb, and back towards the wrist. This retrograde supply means a break can compromise the vascular supply to the proximal fragment, leading to avascular necrosis.
10000996
a
Scaphoid
Concept
Chapter
2693
3865
Scaphoid fractures
Topic
145
Orthopaedics
12746
After a fall on an outstretched hand, which carpal bone is most at risk of proximal avascular necrosis?
a