* "Washboard stomach" refers to very strong,well-definedabdominalmuscles. * Its lateral border is marked by linea semilunaris which is a curved line along the lateral border of the rectus abdominis. * Linea semicircularis (Arcuate line) defines the lower limit of the posterior layer of the rectus sheath * Linea alba is a tendinous median raphe between the two rectus abdominis muscles. * The falx inguinalis (conjoint tendon) is formed by aponeuroses of the internal oblique and transverse abdominal muscles