Extensor carpi radialis brevis

Brevis, not a head of longus

Extensor carpi radialis brevis is a distinct muscle. Its name and similar action can make it easy to confuse with extensor carpi radialis longus.

The two source meshes remain separate in this atlas. Use their labels to identify them before comparing their outlines.

Sources: Loyola anatomy

Lateral elbow to metacarpal III

ECRB arises through the common extensor origin at the humeral lateral epicondyle. Its tendon reaches the dorsal base of the third metacarpal.

The hand and humerus are not loaded in this forearm context. The article supplies an attachment description, not a claim that those landmarks are visible in the current scene.

Sources: Loyola anatomy

A second radial wrist extensor

ECRB contributes to wrist extension and radial deviation. It shares these actions with longus but has its own origin and distal attachment.

The hand and wrist bones are not loaded here. Camera rotation changes the view, not wrist position; this model does not simulate contraction, tendon gliding or a range of motion.

Sources: Loyola anatomy

A variable nerve-branch pattern

Motor supply comes from the radial-nerve system, commonly described through its deep branch. Cadaveric research also documents branches arising from the radial nerve itself or its superficial branch.

Radial recurrent arterial branches contribute to blood supply. The absence of nerves and vessels in this scene prevents direct inspection of these relationships.

The guide describes anatomical variation, not a diagnosis or a map for a clinical procedure.

Sources: Nerve-variation study · Forearm anatomy study

Read the model

Explore extensor carpi radialis brevis in 3D

1. Inspect brevis alone. Start with Isolate enabled, then rotate to see surfaces that overlap in the front view.
2. Compare both extensors in context. Choose Show context and select Longus, then Brevis. Use Fade others to keep the bones visible as reference geometry.
3. Open the companion guide. Select Extensor carpi radialis longus and use its title or Open structure page link. Compare the metacarpal number rather than assuming the two tendons have the same destination.

Sources and editorial status

This guide uses independently written explanations with links to the evidence behind them. Source checking and specialist anatomical review are separate steps; the latter is still pending.

1. Loyola University Chicago — LUMEN, Extensor carpi radialis brevis

   Lateral epicondylar origin, third-metacarpal insertion and wrist actions. Nerve terminology is expanded using the cadaveric study below.

2. Nayak et al. — Extensor carpi radialis brevis origin, nerve supply and its role in lateral epicondylitis (2010)

   Abstract: study of 72 limbs reporting different origins of the motor branch to ECRB. Surg Radiol Anat. 32:207–211; first published online in 2009. No treatment advice reproduced.

3. Anatomy of the nerves, vessels, and muscular compartments of the forearm, as revealed by high-resolution ultrasound. Part 1 (2021)

   Table 2: nerve and arterial supply of the forearm compartments. No ultrasound images are reproduced.

3D geometry and its separate license are credited beneath the viewer. References do not imply endorsement of this site.