Anatomical snuffbox
Fovea radialis
Also known as: radial fossa, tabatière anatomique
A triangular hollow on the radial side of the wrist, seen when the thumb is extended. It is bounded by the APL/EPB and EPL tendons and floored by the scaphoid and trapezium.
Overview
When the thumb is fully extended, a depression appears on the dorsolateral side of the wrist between the tendons of the outcropping thumb muscles. Boundaries: anterior (radial) border, the tendons of abductor pollicis longus and extensor pollicis brevis; posterior (ulnar) border, the tendon of extensor pollicis longus; proximal border, the radial styloid process. Floor: the scaphoid and trapezium, with the tendons of ECRL and ECRB beneath. Contents: the radial artery crosses its floor on its way to the dorsum of the hand (its pulse can be felt here). The cephalic vein begins in the roof, and branches of the superficial radial nerve cross over it.
Parts & subdivisions
- APL and EPB tendons.
- EPL tendon.
- Scaphoid and trapezium.
- Radial artery (deep), cephalic vein (origin, in the roof) and superficial radial nerve branches.
Anatomy
- Relations
Proximally: the radial styloid. Distally: the base of the 1st metacarpal.
Function
- A clinical landmark for scaphoid injury, the radial pulse and the cephalic vein
Clinical significance
Scaphoid fracture
Snuffbox tenderness after a fall on an outstretched hand suggests a scaphoid fracture, even if the initial X-ray is normal. The blood supply enters distally (dorsal carpal branch of the radial artery), so waist and proximal pole fractures risk avascular necrosis of the proximal fragment and non-union. Immobilise the wrist and re-image (MRI or a repeat X-ray at 10–14 days).
Test yourself
After a fall on an outstretched hand, a patient is tender in the anatomical snuffbox. Which tendons form its boundaries?
- FCR and palmaris longus
- APL and EPB laterally (anterior); EPL medially (posterior)
- ECRL and ECRB
- Extensor digitorum and extensor indicis
Answer: APL and EPB laterally (anterior); EPL medially (posterior)
The anterior (lateral) border is abductor pollicis longus with extensor pollicis brevis, and the posterior (medial) border is extensor pollicis longus. The scaphoid forms the floor and the radial artery crosses it, so snuffbox tenderness suggests a scaphoid fracture.
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.