The obturator nerve in human anatomy arises from the

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

divisions of the second, third, and fourth

lumbar nerves The lumbar nerves are the five pairs of spinal nerves emerging from the lumbar vertebrae. They are divided into posterior and anterior divisions. Structure The lumbar nerves are five spinal nerves which arise from either side of the spinal cord b ...

in the

lumbar plexus The lumbar plexus is a web of nerves (a nervous plexus) in the lumbar region of the body which forms part of the larger lumbosacral plexus. It is formed by the Ventral ramus of spinal nerve, divisions of the first four lumbar nerves (L1-L4) and ...

; the branch from the third is the largest, while that from the second is often very small.

Structure

The obturator nerve originates from the anterior divisions of the L2, L3, and L4 spinal nerve roots. It descends through the fibers of the

psoas major The psoas major ( or ; from grc, ψόᾱ, psóā, muscles of the loins) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the iliop ...

, and emerges from its medial border near the brim of the pelvis. It then passes behind the common iliac arteries, and on the lateral side of the

internal iliac artery The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis. Structure The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compa ...

and vein, and runs along the lateral wall of the

lesser pelvis The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reprod ...

, above and in front of the obturator vessels, to the upper part of the

obturator foramen The obturator foramen (Latin foramen obturatum) is the large opening created by the ischium and pubis bones of the pelvis through which nerves and blood vessels pass. Structure It is bounded by a thin, uneven margin, to which a strong membran ...

. Here it enters the thigh, through the

obturator canal The obturator canal is a passageway formed in the obturator foramen by part of the obturator membrane and the pelvis. It connects the pelvis to the thigh. Structure The obturator canal is formed between the obturator membrane and the pelvis. Th ...

, and divides into an anterior and a posterior branch, which are separated at first by some of the fibers of the

obturator externus The external obturator muscle, obturator externus muscle (; OE) is a flat, triangular muscle, which covers the outer surface of the anterior wall of the pelvis. It is sometimes considered part of the medial compartment of thigh, and sometimes c ...

, and lower down by the

adductor brevis The adductor brevis is a muscle in the thigh situated immediately deep to the pectineus and adductor longus. It belongs to the adductor muscle group. The main function of the adductor brevis is to pull the thigh medially. The adductor brevis ...

. An accessory obturator nerve may be present in approximately 8% to 29% of the general population.

Branches

Anterior branch of obturator nerve The anterior branch of the obturator nerve is a branch of the obturator nerve found in the pelvis and leg. It leaves the pelvis in front of the obturator externus and descends anterior to the adductor brevis, and posterior to the pectineus and ...

* Posterior branch of obturator nerve * Cutaneous branch of the obturator nerve

Function

The obturator nerve is responsible for the sensory innervation of the skin of the medial aspect of the

thigh In human anatomy, the thigh is the area between the hip ( pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of ...

. The nerve is also responsible for the motor innervation of the adductor muscles of the

lower limb The human leg, in the general word sense, is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or gluteal region. However, the definition in human anatomy refers only to the section of the lower limb ex ...

( external obturator,Moore, K.L., & Agur, A.M. (2007). ''Essential Clinical Anatomy: Third Edition.'' Baltimore: Lippincott Williams & Wilkins. 336.

adductor longus In the human body, the adductor longus is a skeletal muscle located in the thigh. One of the adductor muscles of the hip, its main function is to adduct the thigh and it is innervated by the obturator nerve. It forms the medial wall of the fem ...

adductor magnus Adductor may refer to: * One of the anatomical terms of motion Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminolo ...

, gracilis) and the pectineus (inconstant). It is, notably, not responsible for the innervation of the obturator internus, despite the similarity in name.Moore, K.L., & Agur, A.M. (2007). ''Essential Clinical Anatomy: Third Edition.'' Baltimore: Lippincott Williams & Wilkins. 345.

Clinical significance

An obturator

nerve block Nerve block or regional nerve blockade is any deliberate interruption of signals traveling along a nerve, often for the purpose of pain relief. Local anesthetic nerve block (sometimes referred to as simply "nerve block") is a short-term block, ...

may be used during knee surgery and

urethral The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra con ...

surgery in combination with other

anaesthetics An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into two ...

Additional images

Image:Gray837.png, Sacral plexus of the right side. Image:Gray236.png, Right hip bone. Internal surface. Image:Gray404.png, Left Levator ani from within. Image:Gray436.png, The Obturator externus. Image:Gray539.png, The arteries of the pelvis. Image:Gray541.png, Variations in origin and course of obturator artery. Image:Gray547.png, The relations of the femoral and abdominal inguinal rings, seen from within the abdomen. Right side. Image:Lumbar_plexus.svg, Plan of lumbar plexus. Image:Gray823.png, The lumbar plexus and its branches. Image:Gray824.png, Deep and superficial dissection of the lumbar plexus. Image:Gray829.png, Dissection of side wall of pelvis showing sacral and pudendal plexuses. File:Slide12w.JPG, Obturator nerve File:Slide7z.JPG, Obturator nerve File:Slide1erer.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view. File:Slide2erer.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view. File:Slide3erer.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view. File:Slide4erer.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view. File:Slide2ewew.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view. File:Slide3ewew.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view. File:Slide1gt.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view File:Slide2gt.JPG, Lumbar and sacral plexus. Deep dissection.Anterior view

References

External links

* * * * ()
cutaneous field at neuroguide.com
{{DEFAULTSORT:Obturator Nerve Nerves of the lower limb and lower torso