J Korean Neurosurg Soc.  2016 May;59(3):282-286. 10.3340/jkns.2016.59.3.282.

A Morphometric Study of the Obturator Nerve around the Obturator Foramen

• Jo SY
• Chang JC
• Bae HG
• Oh JS
• Heo J
• Hwang JC

• KMID: 2192107
• DOI: http://doi.org/10.3340/jkns.2016.59.3.282

Abstract

OBJECTIVE
Obturator neuropathy is a rare condition. Many neurosurgeons are unfamiliar with the obturator nerve anatomy. The purpose of this study was to define obturator nerve landmarks around the obturator foramen.
METHODS
Fourteen cadavers were studied bilaterally to measure the distances from the nerve root to relevant anatomical landmarks near the obturator nerve, including the anterior superior iliac spine (ASIS), the pubic tubercle, the inguinal ligament, the femoral artery, and the adductor longus.
RESULTS
The obturator nerve exits the obturator foramen and travels infero-medially between the adductors longus and brevis. The median distances from the obturator nerve exit zone (ONEZ) to the ASIS and pubic tubercle were 114 mm and 30 mm, respectively. The median horizontal and vertical distances between the pubic tubercle and the ONEZ were 17 mm and 27 mm, respectively. The shortest median distance from the ONEZ to the inguinal ligament was 19 mm. The median inguinal ligament lengths from the ASIS and the median pubic tubercle to the shortest point were 103 mm and 24 mm, respectively. The median obturator nerve lengths between the ONEZ and the adductor longus and femoral artery were 41 mm and 28 mm, respectively.
CONCLUSION
The obturator nerve exits the foramen 17 mm and 27 mm on the horizontal and sagittal planes, respectively, from the pubic tubercle below the pectineus muscle. The shallowest area is approximately one-fifth medially from the inguinal ligament. This study will help improve the accuracy of obturator nerve surgeries to better establish therapeutic plans and decrease complications.

Keyword

Obturator nerve; Obturator foramen; Morphometric study

MeSH Terms

Cadaver
Femoral Artery
Ligaments
Obturator Nerve*
Spine

Figure

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  Fig. 1 Photograph of a cadaver specimen showing an anteroposterior view of the right thigh soft tissue dissection. The obturator nerve exit zone of the foramen (white arrow) was exposed after the pectineus muscle was dissected.

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  Fig. 2 Photograph of a cadaver specimen showing an anteroposterior view of the right thigh between the ASIS, the pubic tubercle, and the obturator nerve exit zone of the foramen after soft tissue dissection. A : the distance from the ASIS to the obturator nerve exit zone of the foramen, B : the distance from the pubic tubercle to the obturator nerve exit zone of the foramen. ASIS : anterior superior iliac spine

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  Fig. 3 Photograph of a cadaver specimen showing an anteroposterior view of the right thigh between the pubic tubercle and the obturator nerve exit zone of the foramen after soft tissue dissection. C : the horizontal distance, D : the vertical distance.

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  Fig. 4 Photograph of a cadaver specimen showing an anteroposterior view of the right thigh between the inguinal ligament and the obturator nerve exit zone of the foramen after soft tissue dissection. E : the shortest distance from the obturator nerve exit zone of the foramen to the inguinal ligament, F : the inguinal ligament length from the ASIS to point E, G : the inguinal ligament length from the pubic tubercle to point E. ASIS : anterior superior iliac spine.

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  Fig. 5 Photograph of a cadaver specimen showing an anteroposterior view of the right thigh between the femoral artery and the obturator nerve exit zone of the foramen after soft tissue dissection. H : the obturator nerve length was exposed between the obturator nerve exit zone of the foramen and the adductor longus, I : the shortest distance from the obturator nerve exit zone of the foramen to the femoral artery.

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