Anatomical snuffbox

It is the important topic of the 1st yrs medical student. Every year one question has been asked in exam.

The anatomical snuffbox (also known as the radial fossa), is a triangular depression found on the lateral aspect of the dorsum of the hand. The anatomical snuff box is a triangular deepening at the level of the carpal bones, specifically, the scaphoid and trapezium bones forming the floor.

BOUNDARIES÷

Ulnar (medial) border: Tendon of the extensor pollicis longus.

Radial (lateral) border: Tendons of the extensor pollicis brevis and abductor pollicis longus.

Proximal border: Styloid process of the radius.

Floor: Carpal bones; scaphoid and trapezium.

Roof: Skin.

Contents÷

The main contents of the anatomical snuffbox are the radial artery, a branch of the radial nerve, and the cephalic vein:

1) Radial artery – crosses the floor of the anatomical snuffbox, then turns medially and travels between the heads of the adductor pollicis muscle.

2) Radial nerve – found in the skin and subcutaneous tissue of the anatomical snuffbox.

3) Cephalic vein – arises from the dorsal venous network of the hand and crosses the anatomical snuffbox to travel up the anterolateral aspect of the forearm.

Clinical significance÷

In the event of a blow to the wrist (e.g falling on an outstretched hand), the scaphoid takes most of the force. If localized pain is reported in the anatomical snuffbox, a fracture of the scaphoid is the most likely cause. The scaphoid has a unique blood supply, which runs distal to proximal. A fracture of the scaphoid can disrupt the blood supply to the proximal portion – this is an emergency. Failure to revascularise the scaphoid can lead to avascular necrosis, and future arthritis for the patient.