persistent pain in the groin and thigh area is a difficult clinical problem to evaluate .
there are many entities that produce groin pain including tendonitis , bursitis , osteitis pubis , stress fracture , sports hernias or athletic pubalgia , nerve entrapment [ 13 ] . in some instances ,
a report of obturator nerve compression , specifically its anterior division , is one possible cause of pain in the adductor region .
subsequent surgical decompression of the anterior division of the obturator nerve has produced favorable results .
the purpose of this article is to describe the various causes of obturator neuropathy , diagnostic tests , as well as various treatment modalities .
key words used for the search were : obturator neuropathy and obturator nerve . a total of 497 articles were found . of these
there were three review articles of which two used more than three case reports . the majority of the other studies used were case reports .
the obturator nerve originates from the anterior division of the ventral rami of the second , third , and fourth lumbar spinal nerves within the psoas major muscle .
the obturator nerve results from the unification of the rami and descends through the psoas muscle to emerge from its medial border at the pelvic brim .
it runs over the pelvic brim into the lesser pelvis , curving anteroinferiorly and following the lateral pelvic wall to pass through the obturator foramen in which it divides into anterior and posterior branches : the anterior branch innervates the adductor longus , gracilis , and adductor brevis muscles and also gives off sensory fibers that innervate the skin and fascia of the medial aspect of the midthigh . the posterior division pierces and innervates the obturator externus .
then it runs between the adductor brevis and magnus muscles and splits into a motor branch that supplies adductor magnus , and a sensory branch to the knee joint to supply the articular capsule , cruciate ligaments , and synovial membrane of the knee joint .
the most common presenting symptom is sensory alteration in the medial thigh [ 5 , 7 ] .
a deep ache may be described in the adductor origin region at the pubic bone and may extend to the medial aspect of the thigh to the knee .
exacerbation of pain may be caused by maneuvers that stretch the nerve either by extension or lateral leg movement .
however , the obturator nerve very rarely provides sensation distal to the knee [ 5 , 7 ] .
despite the fact that many muscles used in thigh adduction are intervated by nerves other than the obturator n. adduction on the affected side is usually weak .
sometimes medial thigh wasting can be observed . with severe injuries , loss of adduction and internal rotation occur . during ambulation ,
the hip is externally rotated and abnormally abducted , which results in a circumducting , wide based gait [ 7 , 10 ] .
ipsilateral loss of the hip adductor tendon reflex can be present , but is only suggestive , not pathognomonic of obturator neuropathy . because this reflex does not always occur in healthy individuals , presence of this reflex on the contralateral
several authors have described injury to the nerve following surgery , hemorrhage , or tumor compression [ 1125 ] . however , for the purpose of this article , the discussion will be limited to sports - related injuries .
described obturator neuropathy in athletes as a result of fascial entrapment as the nerve enters the thigh , specifically in the adductor compartment .
induced by exercise , the pain had a characteristic clinical pattern of medial thigh pain commencing in the region of the adductor muscle origin and radiating distally along the medial thigh , with strenuous exercise .
an anatomic study on cadaver limbs by harvey and bell reinforced the concept that obturator neuropathy is caused by an entrapment syndrome due to the relationship between nerve , vessels , and fascia .
brukner and khan state that there may be  associated weakness or a feeling of a lack of propulsion of the limb during running but numbness is very rarely reported  .
conservative management included rest , physical therapy ( such as ultrasound and interferential treatment ) , soft tissue massage , adductor muscle and pelvic strengthening exercises , oral anti - inflammatory therapy , corticosteroid injection , and groin stretches .
conversely , surgical neurolysis provided better outcomes with athletes returning to competition within several weeks of treatment . at surgery ,
entrapment of the obturator nerve by a thick fascia overlying the short adductor muscle was described . however , reproduction of this postulated entrapment neuropathy by other investigators has yet to be found .
. however , there may be features found on radiograph that may identify a cause of groin pain other than obturator neuropathy . magnetic resonance imaging ( mri )
was used in a previous study to detect the distribution of local anesthetic during a three - in - one block .
mri can also be used to obtain the baseline anatomical structure of the inguinal region of the patients in whom surgery is a possibility and to exclude other causes of groin pain .
mri may detect atrophy of the adductor brevis and longus and gracilis suggestive of denervation and obturator nerve entrapment .
however , it is unable to detect any abnormality of the nerve in the thigh or in the fibro - osseus tunnel .
other imaging such as computed tomography or ultrasound imaging can be helpful for suspected intrapelvic mass lesions entrapping the obturator nerve [ 5 , 7 ] .
scintigraphic bone scan can demonstrate a mild ipsilateral increase in uptake in the region of the pubic ramus , at the origin of the short or long adductor muscle .
but since obturator neuropathy is primarily a soft tissue problem , mri is typically higher yield .
. showed chronic denervation in the short and long adductor muscles of athletes with chronic groin pain attributed to obturator neuropathy .
other authors noted the importance that denervation findings ( fibrillation potentials or high - amplitude , long - duration complex motor unit potentials ) should be consistent with acute or chronic denervation in the hip adductors , but not in other lower extremity muscles such as the iliopsoas or quadriceps muscles .
showed that paraspinal muscle sampling at l-2 , l-3 and l-4 and in other muscles supplied by these nerve roots were normal , excluding a more proximal lesion .
previous authors have tested the validity of applying a local anesthetic block such as lidocaine or bupivacaine to the obturator nerve at the obturator foramen under fluoroscopy [ 30 , 31 ] .
it is proposed that the nerve block should reproduce the patient s weakness , especially after exercise , and should relieve pain from provocative stretches .
presence of paresthesia in the sensory distribution of the obturator nerve over the distal medial thigh provides evidence of accurate localization and adequacy of the nerve block .
if definitive surgical treatment is considered , this test is particularly useful to confirm the diagnosis of obturator involvement and especially useful in delineating between other possible causes of groin pain .
key words used for the search were : obturator neuropathy and obturator nerve . a total of 497 articles were found . of these
the obturator nerve originates from the anterior division of the ventral rami of the second , third , and fourth lumbar spinal nerves within the psoas major muscle .
the obturator nerve results from the unification of the rami and descends through the psoas muscle to emerge from its medial border at the pelvic brim .
it runs over the pelvic brim into the lesser pelvis , curving anteroinferiorly and following the lateral pelvic wall to pass through the obturator foramen in which it divides into anterior and posterior branches : the anterior branch innervates the adductor longus , gracilis , and adductor brevis muscles and also gives off sensory fibers that innervate the skin and fascia of the medial aspect of the midthigh . the posterior division pierces and innervates the obturator externus .
then it runs between the adductor brevis and magnus muscles and splits into a motor branch that supplies adductor magnus , and a sensory branch to the knee joint to supply the articular capsule , cruciate ligaments , and synovial membrane of the knee joint .
the most common presenting symptom is sensory alteration in the medial thigh [ 5 , 7 ] .
a deep ache may be described in the adductor origin region at the pubic bone and may extend to the medial aspect of the thigh to the knee .
exacerbation of pain may be caused by maneuvers that stretch the nerve either by extension or lateral leg movement .
however , the obturator nerve very rarely provides sensation distal to the knee [ 5 , 7 ] .
despite the fact that many muscles used in thigh adduction are intervated by nerves other than the obturator n. adduction on the affected side is usually weak .
sometimes medial thigh wasting can be observed . with severe injuries , loss of adduction and internal rotation
the hip is externally rotated and abnormally abducted , which results in a circumducting , wide based gait [ 7 , 10 ] .
ipsilateral loss of the hip adductor tendon reflex can be present , but is only suggestive , not pathognomonic of obturator neuropathy . because this reflex does not always occur in healthy individuals , presence of this reflex on the contralateral
several authors have described injury to the nerve following surgery , hemorrhage , or tumor compression [ 1125 ] . however , for the purpose of this article , the discussion will be limited to sports - related injuries .
described obturator neuropathy in athletes as a result of fascial entrapment as the nerve enters the thigh , specifically in the adductor compartment .
induced by exercise , the pain had a characteristic clinical pattern of medial thigh pain commencing in the region of the adductor muscle origin and radiating distally along the medial thigh , with strenuous exercise .
an anatomic study on cadaver limbs by harvey and bell reinforced the concept that obturator neuropathy is caused by an entrapment syndrome due to the relationship between nerve , vessels , and fascia .
brukner and khan state that there may be  associated weakness or a feeling of a lack of propulsion of the limb during running but numbness is very rarely reported  .
conservative management included rest , physical therapy ( such as ultrasound and interferential treatment ) , soft tissue massage , adductor muscle and pelvic strengthening exercises , oral anti - inflammatory therapy , corticosteroid injection , and groin stretches .
conversely , surgical neurolysis provided better outcomes with athletes returning to competition within several weeks of treatment . at surgery ,
entrapment of the obturator nerve by a thick fascia overlying the short adductor muscle was described .
however , reproduction of this postulated entrapment neuropathy by other investigators has yet to be found .
plain radiographic studies are normal in persons exhibiting obturator neuropathy . however , there may be features found on radiograph that may identify a cause of groin pain other than obturator neuropathy . magnetic resonance imaging ( mri ) was used in a previous study to detect the distribution of local anesthetic during a three - in - one block .
mri can also be used to obtain the baseline anatomical structure of the inguinal region of the patients in whom surgery is a possibility and to exclude other causes of groin pain .
mri may detect atrophy of the adductor brevis and longus and gracilis suggestive of denervation and obturator nerve entrapment .
however , it is unable to detect any abnormality of the nerve in the thigh or in the fibro - osseus tunnel .
other imaging such as computed tomography or ultrasound imaging can be helpful for suspected intrapelvic mass lesions entrapping the obturator nerve [ 5 , 7 ] .
scintigraphic bone scan can demonstrate a mild ipsilateral increase in uptake in the region of the pubic ramus , at the origin of the short or long adductor muscle .
but since obturator neuropathy is primarily a soft tissue problem , mri is typically higher yield .
. showed chronic denervation in the short and long adductor muscles of athletes with chronic groin pain attributed to obturator neuropathy .
other authors noted the importance that denervation findings ( fibrillation potentials or high - amplitude , long - duration complex motor unit potentials ) should be consistent with acute or chronic denervation in the hip adductors , but not in other lower extremity muscles such as the iliopsoas or quadriceps muscles .
showed that paraspinal muscle sampling at l-2 , l-3 and l-4 and in other muscles supplied by these nerve roots were normal , excluding a more proximal lesion .
previous authors have tested the validity of applying a local anesthetic block such as lidocaine or bupivacaine to the obturator nerve at the obturator foramen under fluoroscopy [ 30 , 31 ] .
it is proposed that the nerve block should reproduce the patient s weakness , especially after exercise , and should relieve pain from provocative stretches .
presence of paresthesia in the sensory distribution of the obturator nerve over the distal medial thigh provides evidence of accurate localization and adequacy of the nerve block . if definitive surgical treatment is considered , this test is particularly useful to confirm the diagnosis of obturator involvement and especially useful in delineating between other possible causes of groin pain .
pharmacologic management of pain and physical therapy to improve strength and to preserve mobility and ambulation may be indicated .
medication can include non - steroidal anti - inflammatory drugs ( nsaid ) or other pain relievers such as acetaminophen .
rest , modification of the activities that initially caused the event , or substituting them with other activities may offer relief . physical therapy , massage , or nerve blocks can all be tried .
however , conservative management may not be a suitable alternative to the high level athlete or in those with refractory treatment
. there may be a temporal relationship between nerve injury , therapy , and recovery .
therefore athletes with diagnosed obturator neuropathy should try only a limited course of conservative therapy .
stated that patients with acute onset of obturator neuropathy had good recovery with conservative management .
conversely , those with chronic neuropathy have less chance for improvement and , thus , result in a poorer outcome .
surgery should be considered in those with pain and weakness resistant to conservative therapy and documented emg changes or response to nerve block .
a rehabilitation plan of physical therapy with gradual return to activities after surgery should be implemented with expected return to activity at 36 weeks .
athletes will present with pain , weakness in leg adduction , and sensory loss over a small area in the medial thigh sometimes just with exercise or exacerbated after exercise .
often , obturator neuropathy is caused by pelvic trauma or surgery so athletes should be questioned regarding previous surgery .
definitive diagnosis is made with electrophysiologic studies and can be confirmed by obturator nerve block with local anesthesia .
surgical exploration should be considered for lesions documented by emg or local nerve block , for those with predisposing risk factors ( prior surgery , pelvic trauma , or hematoma ) and with prolonged or severe lesions .
 obturator neuropathy is a difficult clinical problem to evaluate . 
 one possible cause of pain is due to fascial entrapment of the nerve . 
 symptoms include medial thigh or groin pain , weakness with leg adduction , and sensory loss in the medial thigh of the affected side . 
 radiographic imaging provides limited diagnostic help . 
 mri may detect atrophy in the adductors of the leg . 
 however , it is unable to detect any abnormality of the nerve or in the fibro - osseus tunnel . 
 the best test for diagnosis is by electromyography ( emg ) and can be confirmed by a local nerve block . 
 pharmacologic management of pain and physical therapy can be helpful in the acute phase of injury . 
 surgical decompression of the nerve should be considered for lesions documented by emg or local nerve block , for those with predisposing risk factors ( prior surgery , pelvic trauma , or hematoma ) and with prolonged or severe lesions . 
Introduction
Search strategy
Anatomy
Clinical presentation
Causes
Diagnostic tests
Treatment
Summary