Abstract:
ABSTRACT
Introduction: Obturator nerve arises from the ventral divisions of the second, third, and
fourth lumbar nerves. However, the nerve has also been reported to arise only from the third
and fourth lumbar nerves. The nerve divides into anterior, posterior and hip articular branches
at variable levels in the inguinal region around the obturator canal. The anterior and posterior
branches provide variable subdivisions to provide innervation for medial compartment
muscles of thigh. Accessory obturator nerve forms part of the lumbar plexus and is
occasionally present in 10% of the population.
Objective: The study has been conducted to assess the anatomical variations and distribution
of obturator nerve on Ethiopian cadavers.
Method: Observational based descriptive study design was implemented to assess the
anatomical variations and distribution of obturator nerve on 34 (67sides) embalmed human
specimens in dissection rooms of Anatomy Departments of the selected seven Ethiopian
public universities from October 2017 to February 2018. Anatomy of obturator nerve was
examined bilaterally from origin to its final distribution and the variations and normal
features were recorded and photographed.
Result: A total of 34 cadavers (67 sides; 34 right and 33 left sides) were observed in this
study. Obturator nerve arise from L2, L3 and L4 spinal nerves in 88.1%and from L3 and L4
spinal nerves in 11.9% of the specimens. In 23.9%, 44.8% and 31.3% of specimens the
bifurcation levels of obturator nerve was determined to be intrapelvic, within the obturator
canal and extrapelvic, respectively. The anterior branch subdivided into two, three and four
subdivisions in 9%, 65.7% and 25.4% of the specimens, respectively. Posterior branch
provides two subdivisions in 65.7% and three subdivisions in 34.3% of the specimens. Hip
articular branch most commonly arises from common obturator nerve in 67.2% to provide
sensory innervation to the hip joint. AON was not observed at all in this study.
Conclusion: The study shows that there are important variations with regard to the
prevalence of variations of the root values, the bifurcation levels into its branches around the
obturator canal and the subdivisions of the anterior and posterior branches of the obturator
nerve. Knowledge of these variations is important for pelvic and hip joint surgeries; and for
proper localization and blocking of the nerve along with evaluation of groin pain.
