Fig. 2

a Virtualization of the anterior abdominal wall: On the left side the oblique external muscle is shown, located on top of the three flat muscles of the lateral abdominal wall. On the right-hand side multiple layers were excluded to show the underlying internal oblique muscle and the transversus abdominis. The rectus sheath forms a central part of the functional system. It contains the rectus abdominis and the pyramidalis muscle. b Cadaver study, abdominal wall, ventral view: opened rectus sheath (*); clearly visible is the rectus abdominis muscle (#) with its intramuscular intersections. Red marks and arrow highlight the underlying inferior epigastric artery. c Cadaver study, abdominal wall, dorsal view showing the linea alba, running longitudinally. After removing the aponeurosis of the transversus abdominis muscle (*), the underlying inferior epigastric artery and the rectus abdominis muscle are visible. Arterial branches are mainly located behind intramuscular intersections. The second arrow is pointing to the intramuscular intersections (oblique arrow). The perpendicular arrow marks the linea arcuata. d Virtualization of the normal anatomy, cranial aspect of the linea arcuata, axial view: The ventral and dorsal limitations of the rectus sheath differ between the cranial and caudal aspect of the structure. Superior to the arcuate line, the layers of the aponeurosis of the transversus abdominis muscle are separated and run anteriorly and posteriorly of the musculus rectus abdominis. Inferior to the linea arcuata, the aponeuroses of all three muscles run anteriorly and the rectus sheath is separated from the peritoneum only by the transversalis fascia. e Cadaver study, cross section, axial view showing the rectus abdominis muscle (#). The inferior epigastric artery runs longitudinally within the rectus sheath. The rectus muscle (#) and the rectus sheath. The arrow is pointing to the centrally localized epigastric artery. f Cadaver study, cross section, axial view: Red marks highlight the inferior epigastric artery, a branch of the external iliac artery and the rectus sheath (*). g Virtualization of a rectus sheath hematoma, cranial aspect of the linea arcuata, axial view: Rupture of the rectus abdominis muscle with a significant arterial bleed of the inferior epigastric artery and a subsequent hematoma, typically not surpassing the ipsilateral aspect of the linea alba. h Operative finding: After incision of the lamina anterior fasciae rectus abdominis the partly consolidated hematoma (white arrow) was recovered, measuring approximately 1000 ml of fresh and coagulated blood. The cranial aspect of the rectus abdominis muscle (#) was severed and multiple small intramuscular hematomas were noted. At the caudal aspect a sputtering hemorrhage of the inferior epigastric artery was found and both ends were ligated. i Operative finding: The fascia of the transversus abdominis (*) muscle remained intact. No caesarean section was performed