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Flashcards in Obturator nerve Deck (13):

What is the obturator nerve formed of?

the anterior divisions of the lumbar plexus (L2, L3, L4)


Describe the anatomical course of the obturator nerve

descends through the fibres of the psoas major muscle
emerges from its medial border, running posteriorly to the common iliac arteries
laterally along the pelvic wall to obturator foramen
enters thigh through obturator canal
splits into anterior & posterior divisions


Describe the anatomical course of the anterior division of the obturator nerve

anterior division descends between adductor longus & brevis (medial) muscles towards femoral artery - giving branches to the adductor longs, brevis & gracillis muscles
then pierces the fascia lata to become cutaneous branch of obturator nerve


Describe the anatomical course of the obturator nerve

descends through the obturator externus muscle before passing anteriorly to adductor magnus and giving off branches to supply it


Which muscles does the obturator nerve innervate?

medial compartment of the thigh except hamstring portion of adductor magnus (tibial nerve)


Which muscles are innervated by the obturator nerve? name them. what is their main function?

adductor longus
adductor brevis
adductor magnus (adductor part)
obturator externus
main function: adduct thigh


which muscles adducts the thigh?

adductor longus, brevis, magnus, gracilis


which muscle laterally rotates thigh?

obturator externus


which muscle flexes thigh in the medial compartment?

adductor magnus - adductor part
(hamstring part extends thigh)


which part of skin is innervated by the obturator nerve?

middle part of medial thigh
(anterior medial thigh innervated by anterior cutaneous branch of femoral nerve)


Clinical: damage to the obturator nerve
how can it be damaged? what are the symptoms? how can the patient present?

damaged during surgery involving the pelvis / abdomen
symptoms: numbness, paraesthesia on medial aspect of thigh & weakness in adduction of thigh (adductors)
present: posture & gait problems due to loss of adduction


Clinical: obturator nerve block
when is it used? where is it injected? what can the procedure be carried out under?

used in management of pain after lower limb surgery / chronic hip pain
anaesthetic is injected INFERIOR to pubic tubercle (bone) & lateral to the tendon of adductor longus
procedure carried out under ultrasound guidance


Roots, motor & sensory function

motor: innervates medial compartment of thigh (adductor)
sensory: cutaneous branch innervates skin on medial thigh