Anatomic Study of the Bifurcation of the Obturator Nerve: Application to More Precise Surgical/Procedural Localization.

BACKGROUND: This anatomic study aimed to more precisely locate the bifurcation of the obturator nerve in relationship to the obturator foramen. Such information might improve outcomes in neurotization or other procedures necessitating exposure of the obturator nerve and could increase success rates for obturator nerve blockade. METHODS: Fourteen sides from fresh-frozen cadaveric specimens were used in this study. Dissection of the obturator nerve was performed, and its bifurcation into anterior and posterior branches was documented and classified. Measurements of these branches were also performed. Bifurcations of the obturator nerve were classified as type I when proximal to the obturator foramen, type II when inside the obturator foramen, and type III when distal to the obturator foramen. RESULTS: Type I, type II, and type III obturator nerve bifurcations were observed in 14.3%, 64.3%, and 21.4% of sides, respectively. In type I nerves, the mean distance from the bifurcation of the obturator nerve to the obturator foramen was 15.8 mm, and in type II nerves the mean was 14.0 mm. The mean diameter of the main trunk, anterior branch, and posterior branch was 3.74 mm, 2.64 mm, and 2.28 mm, respectively. CONCLUSIONS: Bifurcation of the obturator nerve can occur proximally, distally, or inside the obturator foramen. Therefore using imaging modalities such as ultrasound is strongly recommended for identifying the main trunk or anterior and posterior branches of the obturator nerve before surgery or other procedures aimed at this nerve due to such anatomic variations.

Relationship of the Obturator Nerve and Psoas Major: Anatomic Study with Application to Avoiding Iatrogenic Injuries.

BACKGROUND: The proximal course of the obturator nerve as related to the psoas major has been described differently among various authors. Because this relationship is important for better understanding of clinical presentations and during surgical approaches, this study aimed to elucidate this anatomy via cadaveric dissection. METHODS: Twenty obturator nerves from 10 white cadaveric specimens underwent dissection. Observations were made of the relationship between the nerve and psoas major muscle. RESULTS: On all sides, the obturator nerve descended posterior to the psoas major and never through it. CONCLUSIONS: These results might be important to clinicians who interpret radiology of this region, to clinicians who treat patients with presumed obturator compression syndromes, or to surgeons who operate near the intracavitary part of the obturator nerve.