Lower Limb Nerve Injuries Flashcards
What system is used to classify nerve inhuries?
Seddon classification
What is the Seddon classification?
Neurapraxia = conduction block Axonotmesis = axons divided Neurotmsis = nerve divided
What does a nerve lesion to the nerves to psoas and illiacus cause?
No pelvic swing when walking
What does a nerve lesion to the femoral nerve cause?
Loss of hip flexion
Loss of knee extension
Loss of sensation
- anterior thigh
- medial leg
What does a nerve lesion to the obturator nerve cause?
Loss of adduction of thigh
Loss of sensation to inner thigh
What does a nerve lesion to the superior gluteal nerve cause?
Loss of abduction at hip - pelvic dip on walking
What does a nerve lesion to the inferior gluteal nerve cause?
Loss of extension at hip
Buttock wasting
What does a nerve lesion to the sciatic nerve cause?
Loss of all motor functions except
- adduction of knee
- flexion of thigh
- extension of knee
Loss of sensation
- lower leg
- foot
What does a nerve lesion to the tibial nerve cause?
Loss of toe flexion
Loss of foot inversion
Loss of sensation
- sole of foot
- inferior aspect of toes
What does a nerve lesion to the common fibular nerve cause?
Loss of toe extension
Loss of foot extension = foot drop
Loss of sensation
- lateral lower leg
- upper foot
What can cause neuropathy?
Injury - stretch/division Extrinsic pressure - abscess/tumour Diabetes Vasculitis Alcohol excess
What is the path of the sciatic nerve?
Exits sciatic notch anterior to piriformis
Travels between adductor magnus + long head of biceps femoris
Bifurcates into tibial and common peroneal nerve in popliteal fossa
What is piriformis syndrome?
Sciatica symptoms involving the overlying piriformis muscle
What is the path of the lateral cutaneous nerve of the thigh?
Passes from lateral border of psoas major across iliac fossa to pierce inguinal ligament
Travels medial to ASIS
Enters thigh deep to fascia lata
Becomes superficial 10cm below inguinal ligament
What does the lateral cutaneous nerve supply?
Supplies the anterolateral aspect of the thigh
What is meralgia paraesthetica?
Compression of the lateral cutaneous nerve of the thigh as it passes through the inguinal ligament or as it pierces the fascia lata
What can cause meralgia paraesthetica?
Obesity
Pregnancy
Tight clothing
Wearing a tool belt
What are the symptoms of meralgia paraesthetica?
Burning or stinging sensation over anterolateral thigh
Tenderness on palpation
Reduced sensation
What aggravates meralgia paraesthetica?
Walking
Standing
What relieves meralgia paraesthetica?
Lying down with hip flexed
What are the effects of a femoral nerve injury?
Weakness of quadriceps
Weakness of hip flexors
Loss of saphenous nerve
Loss of medial + intermediate cutaneous nerves of the thigh
What is the path of the superior gluteal nerve?
Originates from L5-S1 roots
Runs with superior gluteal artery and vein about 5cm from greater trochanter
What is a sign of a superior gluteal nerve injury?
Trendelenburg sign
What is the trendelenburg sign?
Drop of pelcis when lifting leg opposite to weak gluteus medius
What can cause injury to the superior gluteal nerve?
L5 radiculopathy
Surgical trauma during total hip replacement
What is the path of the tibial nerve?
Branch of sciatic nerve
Crosses popliteal fossa
Passes deep to soleus
In posterior compartment between FDL + FHL
Passes deep to flexor retinaculum
Gives off medial calcaneal nerve
Divides into medial and lateral plantar nerves
What is the effect of a tibial nerve injury?
Paralysis of posterior compartment of the leg
Loss of plantar sensation
What is the effect of a superficial peroneal nerve injury?
Loss of active eversion
Sensory loss over dorsum of foot (spares 1st webspace)
Sensory loss to lower anterolateral leg
What can cause injury to the superficial peroneal nerve?
Ankle surgery - lateral approach
Ankle arthroscopy
What is the effect of a the deep peroneal nerve?
Loss of active dorsiflexion = foot drop
Sensory loss in 1st webspace
What can cause saphenous nerve injury?
Venous cut-down
Vein harvest for bypass surgery
What is the effect of a saphenous nerve injury?
Loss of sensation over medial leg
What is the effect of sural nerve injury?
Loss of sensation to lateral border of the foot
