Upper-arm anatomy

Triceps anatomy and training.

The triceps brachii has three heads that converge into a common tendon. All extend the elbow, while the long head also crosses the shoulder and changes length with arm position.

Published and last reviewed September 14, 2026 · 7-minute read

PartsLong, lateral, medial

Main actionElbow extension

Two-joint headLong head

Training contextPresses plus extensions

Short anatomy: the long head begins on the scapula; the lateral and medial heads begin on the humerus. All three attach through the triceps tendon to the ulna. Presses and direct extensions both train the group, but their stimulus is not interchangeable.

Parts and roles

Long head

Crosses the shoulder and elbow, so overhead arm position lengthens it differently from a neutral-arm position.

Lateral head

Begins on the posterior humerus above the radial groove and contributes to elbow extension.

Medial head

Begins below the radial groove and contributes across elbow-extension tasks.

Exercise map

Compound pressesBench, incline, and overhead presses train elbow extension alongside chest and shoulders.

Neutral-arm extensionsPushdowns and similar exercises place the upper arm beside the torso.

Overhead extensionsThe elevated arm changes long-head length and the resistance task.

Close-grip pressingChanges grip and pressing mechanics but remains a multi-muscle movement.

What training studies add

In a within-participant study, 21 adults trained one arm with overhead cable extensions and the other with neutral-arm extensions for 12 weeks. Both conditions increased strength and triceps volume, while growth was greater in the overhead condition, particularly for the long head.

Evidence boundary

This is strong direct evidence for those two cable-extension conditions, not proof that overhead work is always best or required. Compound pressing, other implements, individual comfort, dose, and the rest of the program were not settled by one study.

Weekly sets and recovery

Count direct extensions and the supporting triceps work inside presses, but do not automatically value them as identical sets. Track load, repetitions, range, RIR, and elbow comfort. Use the weekly-sets guide to adjust volume rather than adopting one fixed triceps target.

Frequently asked questions

What are the three heads of the triceps?

The triceps brachii has long, lateral, and medial heads. The long head begins on the scapula, while the lateral and medial heads begin on the humerus. All three join into a common distal tendon at the ulna.

What movement do the triceps perform?

All three triceps heads contribute to elbow extension. Because the long head also crosses the shoulder, arm position changes its length and role.

Do presses count as triceps work?

Bench presses, incline presses, and overhead presses require elbow extension and can provide supporting triceps work. Their contribution is not automatically equivalent to a direct elbow-extension set.

Are overhead extensions always best for triceps?

One direct study found greater triceps growth from overhead cable extensions than neutral-arm extensions in its protocol, particularly for the long head. That result does not establish universal superiority across every exercise, dose, or lifter.

Sources

Triceps muscle anatomy.

NCBI Bookshelf, StatPearls. Updated 2023.

Overhead versus neutral-arm elbow-extension training.

European Journal of Sport Science, 2023. PMID: 35819335.

Adding single-joint work to a multi-joint program.

Eight-week randomized study, 2018. PMID: 30662699.

Explore other muscles

Biceps Chest Lats Side delts Rear delts Quadriceps

Keep presses and extensions in one triceps view.

Forma connects direct and supporting work with weekly sets, optional RIR, progressive overload, and estimated recovery.

Read the methodology Download Forma