triceps

The triceps brachii, commonly called the triceps, is a large muscle located on the posterior aspect of the upper arm. Its primary function is to extend the elbow joint, and the long head also crosses the shoulder, contributing to shoulder extension and adduction. The triceps work together with the elbow flexors as part of the resisting and stabilizing muscles required for many daily activities and athletic movements.

Anatomy and attachments: The muscle has three heads. The long head originates from the infraglenoid tubercle of the scapula. The lateral head originates from the posterior surface of the humerus above the radial groove. The medial head originates from the posterior surface below the radial groove. The three heads converge into a single tendon that inserts on the olecranon of the ulna. Innervation is via the radial nerve (C6–C8). The arterial supply is primarily from the profunda brachii (deep brachial) artery, with contributions from surrounding vessels.

Function: The triceps’ primary action is elbow extension. The long head, crossing the shoulder, can assist in shoulder extension and adduction, especially when the arm is positioned behind the body. The muscle also plays a key role in stabilizing the elbow during weight-bearing and during many pushing movements.

Clinical notes: Common issues include acute strains or chronic tendinopathy of the triceps tendon, particularly in athletes performing repetitive elbow extension. Rupture of the long head is relatively rare. Palpation is often used for assessment, and strength testing is supportive in evaluating function.

Training considerations: Triceps strength and size respond to pressing and elbow-extension exercises, such as push-ups, dips, and various triceps extension movements. Progressive overload and proper technique are important to minimize injury risk.