B6-085 Nerve Lesions of the Lower Extremity Flashcards
dermatome pattern: L5
great toe
dermatome pattern: S2
back of leg
deep laceration to femoral triangle: what pulses to check? [2]
posterior tibial
dorsalis pedis
deep laceration to femoral triangle: where would you evaluate for sensation?
anterior thigh, medial leg
deep laceration to femoral triangle: what nerves are at risk?
femoral
ilioinguinal
lateral femoral cutaneous
causes of femoral nerve damage [3]
vascular disease
retroperitoneal hemorrhage
trauma
why would damage to the femoral nerve cause weakness of thigh flexion?
loss of quadriceps, but still have iliospoas (L1)
why would damage to the femoral nerve cause loss of leg extension?
loss quads
no other muscles do leg extension
why would damage to the femoral nerve cause weakness of lateral rotation of hip?
loss of sartorius
still have glute max
why would damage to the femoral nerve cause weakness of hip abduction?
loss of sartorius
still have glute medius and minimus
why would damage to the femoral nerve cause weakness of knee flexion?
loss of sartorius
still have gracillis, semitendinosus, and gastroc
what would gait look like if femoral n. is damaged?
loss of complete knee extension, compensation by pressing on quad
what deficits of sensation would damage to the femoral nerve cause?
loss of sensation to anterior thigh and medial leg (via saphenous)
innervates the adductors of thigh
obturator
causes of a lesion in obturator [4]
trauma
pelvic fx
childbirth
ovarian cancer
why would damage to obturator result in weakness of hip adduction?
innervates all adductors
still have pectineus (dually innervated by obturator and femoral)
why would damage to obturator result in weakness of hip flexion?
loss of adductor magnus/longus
still have iliopsoas and quads
why would damage to obturator result in weakness of knee flexion?
loss of gracillis
still have gastroc, sartorius, and semitendinosus
why would damage to obturator result in weakness of lateral hip rotation?
loss of obturator externus
still have all other lateral rotators
how would a lesion in obturator affect gait?
circumferential gait (widened due to loss of adduction)
what sensory deficits would a lesion in obturator cause?
loss of sensation of medial thigh
pectineus is dually innervated by [2]
obturator n.
femoral n.
injury to superior gluteal nerve causes what type of gait?
trendelenburg
causes of damage to superior gluteal nerve? [2]
IM injections
penetrating wounds
what motor deficits does damage to the superior gluteal nerve cause?
weakened abduction (loss of glute med, min, and tensor fascia latae)
loss of medial rotation
weakened knee extension (loss of tensor fascia latae)
what sensory deficits does damage to the superior gluteal nerve cause?
does not provide sensory
what nerve does sensory to the buttock?
cluneal nerves
what motor deficits would a patient with a lesion in inferior gluteal nerve demonstrate?
weakness of lateral rotation
weakness of hip extension
(loss of gluteus maximus)
what sensory deficits would a patient with a lesion in inferior gluteal nerve demonstrate?
no sensory
what gait would a patient with a lesion in inferior gluteal nerve demonstrate?
posterior lurch
**lean back due to loss of hip extension
causes of damage to sciatic nerve? [3]
disc hearniation
IM injections
posterior hip dislocations
what gait would a patient with a lesion in the sciatic nerve demonstrate?
loss of heel strike and toe off, requires brace
what sensory deficit would a patient with a lesion in the sciatic nerve demonstrate?
loss of sensation on posterior leg
**but not posterior thigh, that is posterior femoral cutaneous
why would damage to the sciatic cause weakness of thigh extension?
loss of hamstrings
still have glute max
why would damage to the sciatic cause weakness of knee flexion?
loss of hamstrings and gastroc
still have pes anserinus muscles
why would damage to the sciatic cause loss of plantar/dorsi flexion?
sciatic branches into tibial and common fibular nerve, lost all of that
why would damage to the sciatic cause loss of inversion/eversion of foot?
sciatic branches into tibial and common fibular nerve, lost all of that
why would damage to the sciatic cause loss of all foot movements?
sciatic branches into tibial and common fibular nerve, lost all of that
causes of damage to tibial nerve [2]
penetrating wounds
popliteal aneurysm
what would gait look like with damage to the tibial nerve?
loss of toe off, loss of plantar flexion
what sensory deficits would a lesion in tibial nerve cause?
loss of sensation to posterior leg, medial and lateral plantar surface of foot
numbness of dorsum of foot
inability to dorsiflex and evert foot indicates damage to
common fibular
trauma to the head of the fibula can damage the
common fibular n.
what sensory deficits would a lesion in superficial fibular cause?
loss of sensation to distal lateral aspect of foot
what sensory deficits would a lesion in deep fibular cause?
webspace in between 1st and 2nd toe
what motor deficits would a lesion in superficial fibular cause?
weakened foot eversion
weakened plantar flexion
weakened arch supports
what motor deficits would a lesion in deep fibular cause?
loss of dorsiflexion
loss of toe extension
weakness of inversion and eversion
weakened arch support
what gait would a lesion in deep fibular cause?
high steppage gait, foot drop