The hand and wrist is divided into a number of tunnels and anatomical spaces. This simplifies interpretation of clinical findings; pain on palpation of the anatomical snuffbox, is associated with injury to the underlying scaphoid bone. The snuffbox is a triangular region found around the base of the thumb and first metacarpal. The tendons of three thumb muscles define the space. Several structures run within the anatomical snuff box.
The anatomical snuffbox is a triangular shaped region marked by three tendons, and located at the base of the thumb. It is named the ‘snuff box’ as snuff was slang for tobacco, and was snorted from this area in the past. The ulna border of the triangle is marked by the extensor pollicis longus, which inserts onto the distal phalanx of the thumb and is a long extensor of the thumb.
This radial border is marked by two other tendons, the extensor pollicis brevis and the abductor pollicis longus. The radial artery descends from the forearm, and courses radially, passing deep to the tendons of the snuffbox. The artery runs on top of the scaphoid and trapezium carpal bones as it traverses the base of the snuffbox. It will then enter the hand by passing between the two heads of the first dorsal interosseus muscle. Once it passes through it will form the deep palmar arch. The cephalic vein originates in the region of the snuffbox before it to runs radially to drain the dorsal venous network of the hand. The superficial branch of the radial nerve also follows the course of the cephalic vein, and supplies sensation to the dorsal surface of the radial 3 and half fingers and hand (including nailbeds).
Scaphoid fracture - Pain over the anatomical snuffbox may indicate a scaphoid fracture. This is important because fractures of this bone may not been seen in initial x-rays and lead to significant morbidity. The blood supply to the scaphoid is via palmar and dorsal branches from the radial artery. Blood is transmitted in a retrograde fashion to the proximal pole. The palmar branch enters the distal tubercle and supplies the distal third of the bone. The dorsal branch enters through a non-articular ridge on the dorsal surface and supplies the proximal 80% of the bone. Undiagnosed fractures in patients may lead to avascular necrosis of the scaphoid.
Medial border- Extensor pollicis brevis and abductor pollicis longus
Lateral border- Extensor pollicis longus
Floor- Scaphoid and trapezium carpal bones
Lymphatic drainage- Cubital node, supratrochlear nodes, brachial and delto-pectoral lymph nodes.
Lateral two digits- Mainly infraclavicular nodes
The anatomical snuffbox is a triangular region found around the base of the thumb and first metacarpal. The tendons of three thumb muscles define the space, and the radial artery runs in this space in order to enter the hand. Anatomical snuffbox tenderness may indicate scaphoid fracture and may not be seen on x-ray.