Muscle guide · Arms
Also called triceps, back of the arm
The triceps makes up the back of the upper arm. Its long head starts on the shoulder blade just below the socket, and its lateral and medial heads on the back of the arm bone; all three join in one tendon to the point of the elbow.
All three straighten the elbow. The long head also crosses the shoulder, which is why arm position changes how hard it works.
Source 1
| Part | Starts at | Attaches to | What it does |
|---|---|---|---|
| Long head | The shoulder blade, just below the socket | Point of the elbow (olecranon) | Straightens the elbow; helps pull the arm back and down |
| Lateral head | Upper outer back of the arm bone | Olecranon | Straightens the elbow; described as the strongest head |
| Medial head | Lower back of the arm bone | Olecranon | Straightens the elbow |
Source 1
In a 12-week trial, overhead cable extensions grew the long head about 1.5 times as much as extensions with the arm at the side, and the other heads more too, even with lighter loads. Narrow grips on presses add triceps work.
3D demoOverhead cable triceps extensionIntermediate · A cable machine
3D demoSeated one-arm overhead extensionIntermediate · A dumbbell + A bench or box
3D demoTriceps pushdownBeginner · A cable machine
3D demoDumbbell skull crusher (lying triceps extension)Intermediate · A dumbbell + A bench or box
3D demoClose-grip barbell bench pressIntermediate · A barbell + A bench or box
3D demoParallel bar dipAdvanced · Pull-up bar
3D demoDiamond push-upIntermediate · No equipmentArm overhead with the elbow fully bent stretches the long head across both joints.
Triceps tendinitis causes pain at the back of the elbow when straightening it, typically in throwing athletes. Ruptures are rare, usually from a fall on an outstretched hand, often in anabolic steroid users, and complete ruptures need surgery.
Source 1
Each grade rates the evidence for the correction.
In 104 adults who trained one arm for 12 weeks, MRI showed fat loss spread over the body, not concentrated in the trained arm. Spot reduction does not happen.
Source 3
Biceps, triceps and forearms: curls, hammer curls, skull crushers, pushdowns, concentration curls and dips.
35 minBeginner7 movesA dumbbell, A bench or boxA push day workout for chest, shoulders and triceps: bench press, overhead press, incline dumbbell press, lateral raises and pushdowns.
55 minIntermediate10 movesA band, A barbellIt straightens the elbow; its long head also helps pull the arm back and steadies the shoulder.
Overhead extensions grew the triceps about 1.5 times as much as extensions with the arm at the side in a 12-week trial.
No: training one arm did not reduce fat on that arm more than elsewhere.
Anatomy and movement education, not a diagnosis or treatment plan. If you have pain that follows an injury, is severe or getting worse, or comes with numbness, weakness or swelling, get it assessed. Health disclaimer.
