Relation of transversus abdominis muscle to sheath of rectus below costal margin
The left rectus muscle has been detached from its origin and reflected medially. The layers which comprise its sheath have been separated from each other near the lateral border of the muscle. The aponeurosis of the internal oblique (7) contributes to the anterior as well as to the posterior lamina of the sheath at this level. Anteriorly it fuses with the aponeurosis of the external oblique (16). The transversus muscle (14) passes posterior to the aponeurosis of the internal oblique to become aponeurotic approximately midway in its course behind the rectus muscle.
Xiphoid process
Superior epigastric artery
Left rectus abdominis muscle (reflected)
Intercostal nerve VII (branch to rectus muscle)
Tendinous inscriptions
Right rectus abdominis muscle (sheath opened)
Sheath of rectus abdominis muscle (pointers on posterior and anterior lamina derived from aponeurosis of internal oblique)
Internal intercostal muscle
Costochondral junction
Interchondral joint
Rib VII
External intercostal muscle
Intercostal nerve VIII
Transversus abdominis muscle
Aponeurosis of Internal oblique muscle
External oblique muscle (cut across and reflected)
Intercostal nerve X
Internal oblique muscle (cut across)
Sheath of rectus abdominis muscle (anterior layer)