Audio LecturePro Feature Pronator Quadratus 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x The pronator quadratus is a muscle within the deep compartment of the anterior forearm. It is a square-shaped muscle which lies deep to the tendons of flexor pollicis longus and flexor digitorum profundus. Attachments: Originates from the anterior surface of the ulna and attaches to the anterior surface of the radius. Actions: Pronates the forearm. Innervation: Median nerve (anterior interosseous branch). Blood supply: Ulnar artery By TeachMeSeries Ltd (2026) Fig 1Deep flexor muscles of the anterior forearm. 3D ModelPro Feature 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 Frequent questions What is the pronator quadratus muscle? The pronator quadratus is a square-shaped muscle located in the deep compartment of the anterior forearm. It plays a crucial role in the pronation of the forearm. Where does the pronator quadratus originate and insert? This muscle originates from the anterior surface of the ulna and inserts on the anterior surface of the radius. Its positioning allows it to effectively facilitate forearm movements. What is the primary function of the pronator quadratus? The primary function of the pronator quadratus is to pronate the forearm. This action involves rotating the radius over the ulna, allowing for effective hand positioning. Which nerve innervates the pronator quadratus? The pronator quadratus is innervated by the median nerve, specifically through its anterior interosseous branch. This innervation is essential for the muscle's motor function. What is the blood supply for the pronator quadratus? The blood supply to the pronator quadratus is provided by the ulnar artery. This vascular support is vital for the muscle's health and functionality. Rate This Article