In Plain English
The triceps are the large muscles on the back of your upper arm, extending from the shoulder blade and upper arm to the point of the elbow. Made up of three heads, they straighten your elbow, help stabilize the arm during pressing movements, and assist with moving the arm behind the body.
Technical Definition
The triceps refer to the triceps brachii, a three-headed muscle consisting of the long, lateral, and medial heads. The long head originates from the infraglenoid tubercle of the scapula, while the lateral and medial heads originate from the posterior humerus before all three converge into a common tendon inserting onto the olecranon process of the ulna. Together they produce elbow extension, with the long head also contributing to shoulder extension and shoulder adduction due to its origin at the scapula.

















