The hernial sac contents was always motive of concern by part of the surgeons, although still be little studied and known the structure of its wall. The purpose of this work was to evaluate the influences on the inguinal hernial sac of sex, color, age, region of hernial sac, hernia side, width, length, thickness in the presence of smooth muscle fibers (SMF). Also, it is intended to describe the structure of the hernial sacs studied and to present some theories on the SMF source, besides to emphasize the possible significance of knowledge on sacs structure to the hiden pathological condition, identification and the use of the sac itself as a reinforcement instrument on surgical corrections. Samples of 252 hernial sacs obtained during operative therapy of indirects, directs, relapsings, incarcerated inguinal hernias were sent to histopathological study when the samples were stained by Hematoxilin-Eosin (HE) and Gomori trichrome for SMF identification. These were present in 67,9% of the samples and they occurred significantly on indirects and relapsings when were compared to the directs and encarcerateds. With reference to the studied variables, the patients who presented SMF did not difer significantly from those in which the SMF were not found. When the SMF were present, it was often associated to thick blood vessels, suggesting its source from medial layer of vascular wall and might mean a tissue strength as response either to mechanical trauma or other factors of the hernia pathogenesis. It was observed, also, that the hernial sac may host many pathological processes which reach the parietal peritonium, as endometriosis, specific inflamations and hiperplasic processes or even neoplasics, including being able to constitute, in some instances, the first evidence of neoplasm.
Hernial sac; Histophatology; Smooth muscle
