What muscle is commonly known as the "abs"?

The muscle commonly known as the "abs" is the rectus abdominis. This muscle runs vertically along the front of the abdomen and is primarily responsible for flexing the torso, as well as contributing to core stability. When well-developed, the rectus abdominis creates the "six-pack" appearance that is often sought after in fitness and bodybuilding.

The rectus abdominis plays a crucial role not only in movements such as crunches and sit-ups but also supports proper posture and aids in the function of the respiratory system by assisting in forced expiration. Understanding the structure and function of the rectus abdominis is important for those studying anatomy as it highlights the significance of core muscles in overall body mechanics and stability.