1. The anatomical snuffbox

Question 1

Describe the borders of the anatomical snuffbox.

Answer 1

• Ulnar (medial) border: extensor pollicis longus tendon
• Radial (lateral) border: extensor pollicis brevis and adductor pollicis longus tendons
• Proximal border: styloid process of radius
• Floor: scaphoid and trapezium
• Roof: skin

Question 2

Describe the contents of the anatomical snuffbox.

Answer 2

1. radial artery: obliquely crosses floor of snuffbox, deep to extensor tendons.
2. superficial branch of radial nerve: terminal branches run subcutaneously across roof of snuffbox
3. cephalic vein: runs subcutaneously, having just arisen from dorsal venous network of hand

Question 3

What does the superficial branch of the radial nerve go on to innervate?

Answer 3

skin of radial 3 1/2 digits (minus tips) and associated dorsal hand

Question 4

What is localised pain in the anatomical snuffbox a possible symptom of?

Answer 4

scaphoid fracture

Question 5

Why should 2 x-rays be performed in suspected scaphoid fractures?

Answer 5

initial x-ray may not reveal fracture but further x-ray should be performed 10 days later as fracture line may be revealed due to bone resorption

Question 6

Why do scaphoid fractures need to be quickly reduced?

Answer 6

risk of avascular necrosis of proximal scaphoid fragment - can lead to later wrist OA

Question 7

Why is the proximal scaphoid fragment at risk of avascular necrosis?

Answer 7

lateral and distal branches of radial artery provide abundant supply to middle and distal scaphoid but neglect proximal portion which relies on retrograde flow