The Posterior of the Thumb

Question 1

describe the anatomical snuff box

Answer 1

a shallow depression on the lateral aspect of the wrist when the thumb is extended fully

Question 2

Answer 2

Question 3

what are the anatomical snuffbox boundaries? medial, lateral and floor

Answer 3

Ulnar (medial) border: Tendon of the extensor pollicis longus.
Radial (lateral) border: Tendons of the extensor pollicis brevis and abductor pollicis longus.
Floor: Carpal bones; scaphoid and trapezium.

Question 4

what is the difference in action of the extensor pollicis brevis and longus?

Answer 4

• EPB extends MCP and CMC joints of thumb
• EPL extends all joints of thumb: CMC, MCP, IP

Question 5

Describe Colle’s fracture

Answer 5

a common fracture of the distal radius in which there is anterior displacement of the shaft of the radius on the distal aspect of the bone
- caused by falling onto an extended wrist

Question 6

describe a Smith’s fracture

Answer 6

fracture of the distal radius in which there is posterior displacement of the radius on the distal aspect of the bone
- caused by falling onto a flexed wrist

Question 7

what is the most fractured carpal bone?

Answer 7

scaphoid fractures