part of part of immediately deep to immediately superficial to has muscle origin has muscle origin has muscle insertion has muscle insertion transversus abdominis muscle xiphoid process rib abdominal external oblique muscle abdominal internal oblique muscle http://upload.wikimedia.org/wikipedia/commons/3/32/Illu_trunk_muscles.jpg abdominal internal oblique Behind the thorax, the lateral group (of muscles in reptiles and mammals) remains essentially as for amphibians. (It breaks into three sheet-like layers: external oblique muscle, the internal oblique, and the transversus). More anteriorly, however, the ribs, now enlarged, penetrate and alter this group of muscles. The transversus is excluded from the thorax and the external and internal obliques become, respectively, the external and internal intercostal muscles, which contribute to the new function of ventilation of the lungs.[well established][VHOG] EHDAA:8250 MA:0002346 internal oblique abdominis muscle The lateral abdominal wall muscle that is deep to the external oblique and superficial to the transversus. Wikipedia:Abdominal_internal_oblique_muscle musculus obliquus internus abdominis obliqui internus internal oblique muscle NCIT:C32857 VHOG:0000789 obliquus internus abdominis muscle UBERON:0005454 EHDAA2:0000879 internal abdominal oblique internal abdominal oblique muscle obliquus internus abdominis FMA:13891 obliquus internus UMLS:C1512878 internal oblique abdominal obliquus internus abdominis muscle internal oblique abdominis EMAPA:18163 obliquus internus abdominis internal oblique abdominal internal oblique muscle SCTID:244947001 inguinal ligament anterior abdominal wall skeletal muscle organ, vertebrate abdominal oblique muscle