12 - Variations in the Branching Pattern of the Obturator Nerve with Focus on the Branches of the Common Trunk

Poster Board Number: 12
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Odd poster #s – first hour
Even poster #s – second hour

Abstract Body : Introduction & Objectives: The obturator nerve is one of the important nerves of the thigh. It takes origin from the lumbar plexus, passes along the lateral pelvic wall and then courses in the superior medial compartment of the thigh by passing through the obturator foramen. The nerve along with its divisions gives many branches throughout its course. Though the branches of the divisions have been well documented, the branches of the trunk of the obturator nerve and their fate remain underrepresented. This study is aimed at understanding the branches of the common trunk of the obturator nerve while also exploring the branches of the divisions.

Materials and Methods:
23 formalin-fixed cadavers were dissected to observe the course and branches of the right obturator nerve in the pelvic cavity and the superior medial compartment of the thigh. The obturator foramen was opened by taking out part of the superior pubic ramus and the course of the common trunk of the nerve and its branches was examined.

Results: In 82.6 % (19/23) of the bodies, the common trunk of the obturator nerve gave at least one branch before entering the obturator foramen. This branch supplied the obturator internus muscle in 47.3% (9/19) of the bodies; only the obturator externus muscle in 26.3% (5/19) of the bodies; only the hip joint in 10.5% (2/19) of the bodies, and in 15.7% (3/19) of the bodies it divided to supply the hip joint and the obturator externus muscle.

Conclusion: It is well known that there is a high anatomic variability in the obturator nerve. The anatomy of branches of the trunk is also highly variable.

Significance: This study improves our understanding of the role of the obturator nerve in the innervation of the hip joint. Some fibers of the obturator internus muscle are also innervated by the obturator nerve rather than the nerve to the obturator internus. These variations may be relevant to the development of therapies to address injury of the obturator nerve at the pelvic brim. The author thanks the individuals who donated their bodies and tissues for the advancement of education and research, which were provided by the UC Anatomical Materials Programs.