Triceps Brachii - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x The triceps brachii is a muscle in the posterior compartment of the upper arm. It is a large horseshoe-shaped muscle, which forms the majority of the muscle bulk of the upper arm. Attachments: Long head originates from the infraglenoid tubercle of the scapula. Lateral head originates from the humerus (superior to the radial groove). Medial head originates from the humerus (inferior to the radial groove). Distally, the heads converge into one tendon which inserts onto the olecranon of the ulna. Function: Extension of the arm at the elbow. Blood Supply: Deep bracial (profunda brachii) artery Innervation: Radial nerve By TeachMeSeries Ltd (2026) Fig 1The long and lateral heads of the triceps brachii. 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 Prosection of the muscles of the posterior shoulder and upper arm, demonstrating the quadrangular space. Prosection of the muscles of the posterior shoulder and upper arm, demonstrating the quadrangular space. 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 triceps brachii? The triceps brachii is a large, horseshoe-shaped muscle located in the posterior compartment of the upper arm. It constitutes the primary muscle mass of the upper arm and is essential for arm extension at the elbow. Where does the triceps brachii attach? The triceps brachii has three heads with distinct origins: the long head originates from the infraglenoid tubercle of the scapula, the lateral head from the humerus above the radial groove, and the medial head from the humerus below the radial groove. All heads converge into a single tendon that inserts onto the olecranon of the ulna. What is the primary function of the triceps brachii? The main function of the triceps brachii is to extend the arm at the elbow joint. This action is crucial for various movements involving pushing and lifting. What supplies blood to the triceps brachii? The triceps brachii receives its blood supply from the deep brachial (profunda brachii) artery. This ensures adequate oxygen and nutrients for muscle function. Which nerve innervates the triceps brachii? The triceps brachii is innervated by the radial nerve. This nerve is responsible for transmitting signals that facilitate muscle contraction and movement. Rate This Article