Defining the Anatomy of the Tendinous Intersections of the Rectus Abdominis Muscle and Their Clinical Implications in Functional Muscle Neurotization

PURPOSE: Little is known about the definitive course of the tendinous intersections from anterior to posterior through the rectus abdominis (RA) muscle. The implications of a full thickness intersection may have effects on the ability to neurotize the RA. We hypothesized that these tendinous inscriptions would be fully adherent to the anterior rectus sheath, but there would be an incomplete penetrance into the posterior surface, thereby allowing for muscle fibers and neurovascular structures to run the entire course of the RA muscle. METHODS: Fifty-five cadaveric, hemiabdominal walls were evaluated. Measurements were taken of RA muscle thickness, depth of penetrance of the tendinous intersections, and intersection thickness. RESULTS: Of the 32 cadavers, 2 had 4 paired tendinous intersections and the remaining 30 cadavers had 3 paired tendinous intersections. Rectus abdominis muscle belly tended to be thicker at midbelly, between intersections than at the level of the corresponding intersection. A total of 168 tendinous intersections were assessed. Thirty (18%) of these inscriptions proved to be full thickness extending from anterior rectus sheath to posterior rectus sheath without any intervening muscle or neurovascular structures. Twenty-three (42%) of the 55 hemiabdomens assessed had at least one full-thickness tendinous intersection. CONCLUSIONS: The majority of RA muscles have 3 paired tendinous intersections. Most intersections are incomplete and only encompass the anterior rectus sheath. However, there may be a higher percentage of full-thickness intersections than previously appreciated and the clinical relevance behind these remains unclear.