Its origins interdigitate with the pars costalis of the diaphragm. The transversus abdominis is attached to the inner oblique abdominal muscles (musculus obliquus internus abdominis), and it merges into an aponeurosis (tendon plate) together with the obliques to form the linea alba.
M. Transversus Abdominis
Origin
Iliac crest, inguinal ligament, thoracolumbar fascia, and costal cartilages 7-12
Insertion
Linea alba, Crista pubica
Function
compression of the viscera of the abdomen, lowering of the ribs, actions of exhalation
Innervation
N. intercostalis, N. subcostalis, N. ilioinguinalis, N. iliohypogastricus