The musculus transverse abdominis, also known simply as the transverse abdominis or TVA muscle belongs to the group of abdominal muscles that are collectively referred to as the 'core'. The name comes from the direction of its fibers, which run across the abdomen. This is the deepest layer of muscle in the abdomen and they lie beneath the internal oblique muscle.


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

Iliac crest, inguinal ligament, thoracolumbar fascia, and costal cartilages 7-12
Linea alba, Crista pubica
compression of  the viscera of the abdomen, lowering of the ribs, actions of exhalation
N. intercostalis, N. subcostalis, N. ilioinguinalis, N. iliohypogastricus