Learning Objectives
By the end of this section, you should be able to:
- Describe the location and surface anatomy of the anatomical snuffbox
- Identify its borders, floor, roof, and contents
- Explain the clinical significance of the anatomical snuffbox, particularly in scaphoid fractures
The anatomical snuffbox (also known as the radial fossa) is a triangular depression located on the lateral aspect of the dorsum of the hand, at the level of the carpal bones. It becomes most prominent when the thumb is extended.
Historically, this hollow was used to hold powdered tobacco (“snuff”) before inhalation, which explains the origin of the term snuffbox. This section reviews the anatomy of the anatomical snuffbox, including its borders, contents, and clinical relevance.
Borders
The anatomical snuffbox is triangular in shape and is defined by three borders, along with a floor and a roof:
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 and superficial fascia
Important note: The borders of the anatomical snuffbox are formed by tendons, not muscle bellies. Anatomical terms such as medial and lateral refer to the anatomical position (forearm supinated). Care is required when describing these borders clinically, as the forearm is usually pronated during examination.
Contents
The anatomical snuffbox contains several important neurovascular structures:
Radial artery
The radial artery crosses the floor of the snuffbox, then turns medially to pass between the heads of the adductor pollicis muscle. In some individuals, the radial pulse may be palpated in the proximal part of the snuffbox.
Superficial branch of the radial nerve
Located within the skin and subcutaneous tissue, this nerve provides sensory innervation to:
- The dorsal surface of the lateral three and a half digits
- The corresponding area of the dorsum of the hand
Cephalic vein
Originates from the dorsal venous network of the hand and crosses the anatomical snuffbox before ascending along the anterolateral aspect of the forearm.
