External oblique abdominal muscle: A new look on its blood supply and innervation

Abstract

Numerous reports have discussed the use of the external oblique abdominal muscle as a pedicled or a free flap for defect coverage. A detailed description of the supplying vessels and nerves is a prerequisite for successful tissue transfer but so far is not available in the literature. A study of the arteries and nerves supplying the external oblique abdominal muscle was carried out in 42 cadavers after injection of a mixture of latex and bariumsulfate. In seven fresh cadavers the motor branches were identified with the Karnovsky technique. Three different groups of arteries were identified as the nurturing vessels. The cranial part of the muscle is supplied by two branches of the intercostal arteries. While the lateral branches run on the outer surface of the muscle together with the nerves, the anterior branches enter the muscle from its inner surface. The caudal part of the muscle derives its main blood supply from one or two branches of the deep circumflex iliac artery (94.7%) or the iliolumbar artery (5.3%). The external oblique abdominal muscle is innervated by motor branches of the lateral cutaneous branches of the anterior spinal nerves in a segmental pattern. With the exception of the subcostal nerve the motor branches enter the outer surface of the muscle digitation arising from the rib above. The results show that the cranial half of the external oblique abdominal muscle has a strictly segmental blood and nerve supply while the caudal half of the muscle derives its main blood supply from one artery but still shows a segmental innervation.

Covering of an exposed vascular graft in the groin with an external oblique muscle rotational flap

“…The external oblique muscle is a Type V muscle with both dominant and multiple segmental vascular pedicles [7]. The dominant pedicles are one or two branches of either the deep circumflex iliac artery (94.7%) or the iliolumbar artery (5.3%) [8]. The segmental vascular supply is derived from the 5th through 12th posterior intercostal arteries.…”

The Superiorly Based Partial Rectus Abdominis and External Oblique Flap: A New Technique for Breast Asymmetry Reconstruction

“… 9 , 11 , 12 The muscle was initially thought to have a purely segmental blood supply from cutaneous perforators from the lower 8 posterior intercostal arteries. 12 With arterial injection, the studies by Kuzbari et al 9 and Schlenz et al 11 demonstrated additional significant blood supply from the deep circumflex iliac artery. The intercostal perforators to the external oblique muscle are placed along an anteriorly convex line, which curves infero-posteriorly toward the lumbar fascia from the level of the fifth rib in the mid-clavicular plane.…”

Three-Component Model of the Spinal Nerve Branching Pattern, based on the View of the Lateral Somitic Frontier and Experimental Validation

“…The motor branch to the external oblique abdominis muscle takes a similar trajectory to those of the nerves described above. The nerve branch to the external oblique abdominis muscle diverges, shortly after the parental lateral cutaneous branch appears on the surface of the body wall, and then runs on the outer fascial surface to enter the muscles from its surface (Sato, 1973;Schlenz et al, 1999). On the other hand, direct twigs innervate the internal oblique abdominis and traverse abdominis muscles from the intercostal nerve itself that runs in the deep intermuscular space.…”

“…The external oblique abdominis muscle is one that belongs to the ventral outer body wall class, and receives a motor branch from the lateral cutaneous branch in the lower thoracic region (Sato, 1973;Sakamoto et al, 1996;Schlenz et al, 1999;Figure 3). No muscle in the dorsal outer body wall class is in the thoracic region.…”