Inclusive Anatomy
Anatomy
Structure
The dorsal tubercle of the radius is a palpable bony prominence located on the dorsal surface of the distal radius at the level of the wrist.[1] It exhibits considerable anatomical variation in size and morphology. Reported measurements indicate a height ranging from approximately 2–6 mm and a length between 6 and 26 mm.[1,2]
The tubercle lies between the grooves for the extensor tendons and serves as an important surface landmark on the dorsum of the wrist.[1]
Function
The dorsal tubercle of the radius functions as a pulley for the tendon of the extensor pollicis longus, which changes direction by approximately 45 degrees as it courses around the medial aspect of the tubercle toward the thumb.[2]
This mechanical redirection optimizes tendon leverage during thumb extension. Because of its consistent location, the dorsal tubercle serves as a valuable anatomical landmark in wrist arthroscopy and other surgical procedures involving the dorsal wrist.[2] Hyperextension injuries or fractures involving the dorsal tubercle may increase mechanical stress on the extensor pollicis longus tendon, potentially leading to tendon irritation or delayed rupture.[2,3]
References
Moore KL, Dalley II AF, Agur AMR. Clinically Oriented Anatomy. 8th ed. Wolters Kluwer; 2018.
Chan WY, Chong LR. Anatomical Variants of Lister’s Tubercle: A New Morphological Classification Based on Magnetic Resonance Imaging. Korean Journal of Radiology. 2017;18(6):957-963.
Stahl S, Wolff TW. Delayed rupture of the extensor pollicis longus tendon after nonunion of a fracture of the dorsal radial tubercle. Journal of Hand Surgery. 1988;13(3):338-341.