The muscle under the breast bone is the pectoralis major.
Pectoralis Major: Details
The pectoralis major is a large, fan-shaped muscle located in the anterior chest wall.
- Location: It is situated underneath the breast tissue.
- Description: It's the most superior and largest muscle on the anterior chest wall.
- Function: It forms the anterior wall of the axilla (armpit).
In essence, based on the provided reference, the pectoralis major is the primary muscle underlying the breast tissue and, therefore, lies beneath the breast bone (sternum) in the chest region.
