triceps brachii

The triceps brachii muscle (Latin for 'three-headed' muscle of the arm, it is called a three headed muscle because there are three bundles of muscle, each of different origin, joining together at the elbow) is the large muscle on the back of the human upper limb. It is the muscle principally responsible for extension of the elbow joint (i.e. straightening of the arm). Though a similarly-named muscle, the triceps surae, is found on the lower leg, the triceps brachii is commonly called simply the 'triceps'. [WP,unvetted]. Every claim on this page comes from the Leumas anatomy graph and carries its source.

What the triceps brachii is

The triceps brachii muscle (Latin for 'three-headed' muscle of the arm, it is called a three headed muscle because there are three bundles of muscle, each of different origin, joining together at the elbow) is the large muscle on the back of the human upper limb. It is the muscle principally responsible for extension of the elbow joint (i.e. straightening of the arm). Though a similarly-named muscle, the triceps surae, is found on the lower leg, the triceps brachii is commonly called simply the 'triceps'. [WP,unvetted]. The atlas records it as a muscle at the organ scale in the human body.

Where the triceps brachii is

It sits in the upper limb, within the muscular system. Positioned deliberately as part of this species body plan.

What the triceps brachii connects to

The atlas records 11 typed relationships for it, across 7 kinds of connection. part of forelimb stylopod.

Supply and innervation

Innervation: axillary nerve and radial nerve.

Also called

Also recorded as triceps, triceps brachii muscle, musculus triceps brachii and triceps muscle. Searching any of those names reaches this page.

Source

Uberon multi-species anatomy ontology (Mungall et al.), CC BY 4.0. Term UBERON:0001509, version 2026-06-19, retrieved 2026-08-24. Licence: CC-BY-4.0.

• Part of: forelimb stylopod.
• A kind of: forelimb stylopod muscle, muscle of shoulder and skeletal muscle organ, vertebrate.
• Attaches to: tendon of triceps brachii.
• Innervated by: axillary nerve and radial nerve.
• originates from: humerus and scapula.
• antagonist of: biceps brachii.
• inserts into: olecranon.

Questions

Where is the triceps brachii?

It sits in the upper limb, within the muscular system. Positioned deliberately as part of this species body plan.

What does the triceps brachii connect to?

Part of: forelimb stylopod.

Is the triceps brachii the same in other species?

Leumas holds the same relationship vocabulary for every species it carries, so where another dataset records this structure you can put the two side by side on /compare.