Internal Oblique Muscle ‐ "he's the guy in the reconstruction of the abdominal wall” ‐ a conceptual reflection on hernioplasties from the Anatomist's point of view
Authors: Barros Mirna Duarte , Mendes Carlos José Lazzarini 
Published: April 2020

IntroductionAbdominal wall (AW) hernia surgery, mainly the giant and complex ones, is still a challenge. The external oblique muscle (EOM) aponeurosis surgical section, promoting the displacement of the internal oblique muscle (IOM), described as the Anterior Separation of Components (ASC) and the surgical section of the abdominal transverse muscle (ATM), with the displacement of the transversal fascia (TF), called Transversus Abdominis Muscle Release (TAR), are consecrated alternatives. The objective of this paper was to present morphological and functional reasons, based on the literature, for the importance of the internal oblique muscle (IOM) as the foundation for the association of the techniques cited above.MethodA systematic revision of the systemic, topographical and applicable‐to‐clinical‐care anatomy, the AW muscles and aponeuroses, the “core muscle” concept and the thoracolumbar aponeurosis (TCA) and integrity of the IOM associated with the ASC & TAR (Figure
1).ResultsIn this revision, the myoaponeurotic unit of the IOM remains unaltered after the ASC & TAR.Discussion and ConclusionConnell et al., 2003 concluded that the AW stress injury occurs in the eccentric contracture phase, unlike hernias, when the musculature promotes concentric contracture.Geffen et al., 2004 state that there is not sufficient abdominal straight muscle posterior blade slip resulting from the ASC, not occurring interference in the IOM.Tanaka et al., 2007 reported similarities in the musculatures of middle‐aged men and young sedentary men at the umbilical level, without differences in the IOM.As for the TCA, Gatton et al., 2010 demonstrated that, in the 3D biomechanics, the abdominal muscles contribute to the lumbar spine extension, valuing the role of the IOM in the TCA.Kim et al., 2012 demonstrated that the IOM is the main protagonist in the expiratory concentric force in smokers, becoming hypertrophied and valuing the TCA biomechanics.De Silva et al., 2014 determined the AW width following the TAR and medial line reconstruction, demonstrating the hypertrophy of the IOM and EOM.Pauli et al., 2014 presented the association ASC & TAR as the best approach in the recurrent hernia following the ASC.Linek et al., 2015 studying the size of the AW muscles at rest and during the abdominal traction manuever in healthy adolescents, concluded that the IOM has always been the thickest and the ATM, the thinnest.Petro et al., 2015 reported the ASC & TAR as having low perioperative morbidity.Lazzarini et al., 2017 presented the Teaching Model for Reconstruction of the Abdominal Wall via the Separation of Anterior and Posterior Components Technique, showing that the IOM and its aponeurosis can be visualized integrally and in connection with the TCA.The association ASC & TAR, conceptually and morphologically is possible, revealing the independence of the IOM as support in the restraint of the abdominal wall. Therefore, there is sufficient information in the literature which can demystify the premise that the simultaneous use of the techniques ASC & TAR would result in the functional instability of the AW.1. external oblique muscle aponeurosis, 2. Incision in external oblique muscle aponeurosis, 3. Semilunar line, 4. anterior laminae of rectus sheat, 5. umbilical scar, 6. internal oblique muscle, 7. internal oblique muscle aponeurosis.Figure 1S. superior, I. inferior, M. medial, 1. anterior laminae of rectus sheat, 2. rectus abdominis muscle, 3. posterior laminae of rectus sheat, 4. neurovascular bundle, 5. transversus abdominis muscle, 6. transversal fascia, 7. external oblique muscle aponeurosis.Figure 2