Extensor Indicis - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x The extensor indicis is a muscle within the deep compartment of the posterior forearm. The tendon of the extensor indicis passes through the 4th extensor compartment at the wrist. It allows extension of index finger to be independent of the other digits. Attachments: Originates from the posterior surface of the ulna and interosseous membrane. Attaches to the extensor hood of the index finger. Actions: Extension of the index finger at the interphalangeal and metacarpophalangeal joints. Innervation: Radial nerve (posterior interosseous branch). Blood supply: Ulnar artery By TeachMeSeries Ltd (2026) Fig 1Muscles in the deep layer of the posterior forearm. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Pro Feature - Dissection Atlas You've Discovered a Pro Feature Access our Dissection Image Library Enhance your understanding with high-resolution dissection images showcasing real-life anatomy. Learn More Frequent questions What is the extensor indicis muscle? The extensor indicis is a muscle located in the deep compartment of the posterior forearm. It plays a crucial role in extending the index finger independently from the other fingers. Where does the extensor indicis originate and attach? The muscle originates from the posterior surface of the ulna and the interosseous membrane, and it attaches to the extensor hood of the index finger. This positioning allows for precise movements of the index finger. What actions does the extensor indicis facilitate? The primary action of the extensor indicis is to extend the index finger at both the interphalangeal and metacarpophalangeal joints. This enables independent extension, enhancing hand function. Which nerve innervates the extensor indicis? The extensor indicis is innervated by the radial nerve, specifically through its posterior interosseous branch. This nerve supply is essential for the muscle's function in finger extension. What is the blood supply to the extensor indicis? The extensor indicis receives its blood supply from the ulnar artery. This vascularisation supports the muscle's metabolic needs during its actions. Rate This Article