posterior layer of rectus sheath

pos·te·ri·or lay·er of rec·tus sheath

[TA] the portion of the sheath of the rectus abdominis muscle that lies posterior to the muscle covering only its upper two thirds; it is formed by contributions from the aponeuroses of the internal oblique and transversus abdominis muscles; its free inferior margin forms the arcuate line; it is deficient below this, the posterior aspect of the muscle being covered only by transversalis fascia and peritoneum. Synonym(s): lamina posterior vaginae musculi recti abdominis [TA]