Simulation of the human muscular system has multiple applications in biomechanics, biomedicine and in the study of motion in general. Mechanical alterations of the normal functioning in the inguinal area ("inguinal shutter") seems to be involved in the genesis of hernias in adults, but the role of this anatomical mechanisms is poorly understood. A finite element model for the mechanics of the internal oblique muscle allowed creating a dynamic model of the inguinal region applicable to the study of the shutter mechanism as a defence mechanism of contention of the abdominal viscera against development of an inguinal hernia.