Revisiting the obturator nerve anatomy with a nerve blocking perspective

Abstract

Objectives: Accurate nerve block is important for the success of local anesthesia-assisted surgery. Failure to consider the anatomical variations of the targeted nerve anatomy can lead to failure of anesthetic interventions. Given the distinct nature of the obturator nerve, blocking the nerve during clinical procedures is one such problematic situation. The aim of this article is to revisit the anatomy of the obturator nerve in adult cadavers and fetuses in order to discuss in detail its relationship with the obturator nerve block from an anatomical perspective. Methods: Obturator nerve and its branches were exposed at the posterior wall of the abdomen, lateral wall of the lesser pelvis and anterior aspect of the thigh region in 47 fetuses and 10 adult cadavers. Then, various anatomical variations and morphometry of the obturator nerve were evaluated and measured in detail. Results: In adult cadavers, the anterior and posterior branches branched 40% in the obturator canal and 60% in the extra-pelvic region, with no branching in the pelvis. In fetuses, the obturator nerve divided into its main branches 8.5% in the pelvis, 33% in the canal and 58.5% distal to the canal. Regarding the muscular branching of the obturator nerve, all adult cadavers showed three fully traceable branches from the anterior and a single branch from the posterior branch. Conclusion: Our findings regarding the variable branching pattern of the obturator nerve anatomy from the nerve block perspective may help anesthesiologists to improve the success of obturator nerve block by incorporating results from the current and limited number of anatomical data sets.

Keywords

• fetal anatomy
• obturator nerve
• regional anesthetic techniques

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