Rectus abdominis: A major abdominal muscle that extends along the front of the abdomen, from the sternum down to the pubic bone, contributing to spinal stability and movement.
Transverse abdominis: The deepest layer of abdominal muscles that wraps around the torso from front to back, acting like a corset to enhance core stability.
Tendinous intersections: Horizontal bands of tissue that segmentally cross the rectus abdominis muscle, giving it a segmented appearance often referred to as a "six-pack.