Tendon Sheath of the Extensor Carpi Radialis Brevis, Posterior View

Description

Arising from the lateral epicondyle and passing distally along the dorsoradial forearm, the extensor carpi radialis brevis (ECRB) tendon is shown from a posterior perspective as it approaches the wrist under the extensor retinaculum. A synovial tendon sheath (peritendinous tunnel) surrounds the tendon as it tracks superficial to the dorsal carpal bones and toward its insertion on the dorsal base of the third metacarpal. Beneath it, the hand skeleton is rendered in detail, with the distal radius and carpal rows proximal to the metacarpals, and the phalanges extending distally. Clean landmarks. Understanding the ECRB tendon sheath matters because the tendon’s friction environment changes where it transitions beneath the extensor retinaculum into the second dorsal compartment, a region where synovial thickening, peritendinitis, or post-traumatic scarring can tether glide and limit wrist extension. This anatomy also frames differential diagnosis for dorsoradial wrist pain, separating ECRB-related tenosynovitis and intersection-type friction syndromes from first-compartment De Quervain disease, and it supports surgical planning for dorsal compartment release while protecting the superficial branch of the radial nerve and adjacent extensor carpi radialis longus. Use this plate in upper limb anatomy courses, hand therapy teaching materials, and orthopedic or sports medicine publications that need a clear posterior map of the extensor tendons against the carpals, metacarpals, and phalanges. It also fits operative notes, patient education on dorsal wrist tendon sheath inflammation, and exam prep for compartment-based extensor tendon anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.