The triceps and biceps brachii are both muscles that are found in the arm. The biceps brachii muscle is found in the lower arm, and the triceps brachii muscle is found in the upper arm.
The biceps brachii muscle is commonly referred to simply as the biceps muscle. It's a skeletal muscle that helps the elbow and shoulder move. It's a double-headed muscle and has two points of origin in the shoulder. The two points of origin of the biceps brachii muscle join together and end near the elbow. The triceps brachii muscle is the main muscle in the upper arm. It runs along the humerus bone between the shoulder and the elbow. The triceps brachii muscle works with the biceps brachii muscle to extend and retract the forearm.