Developing 'Boulder Shoulders': Understanding the Three Heads of the Deltoid

Want the "capped" look that makes your waist look smaller and your upper body more powerful? It's all in the shoulders. But to get "3D" delts, you need to understand that the shoulder is not one muscle, but three distinct heads.

1. The Anterior (Front) Deltoid

This head is responsible for lifting your arm forward. It gets a lot of work during chest presses, but you can isolate it with front raises. Check the "Deltoid" section in our Muscle Explorer for specific home and gym variations.

2. The Lateral (Side) Deltoid

This is the head that provides width. Lateral raises (with dumbbells or cables) are the primary way to target this area. Because the lateral delt is small, focus on high reps and perfect form rather than heavy weight.

Build 3D Shoulders

Target all three heads of the deltoid with our interactive guide.

Click the image above to open Muscle Explorer.

3. The Posterior (Rear) Deltoid

The most neglected part of the shoulder. Found on the back, it's responsible for horizontal abduction (pulling your arm back). Training it is crucial for shoulder health and a complete "look." Move to the "Back" view in our tool to find Rear Delt exercises.

Conclusion

To build truly impressive shoulders, you can't just press. You need a variety of movements that hit all three heads of the deltoid. Use the interactive map to visualize each one before you pick up the weights.