Lower limb - nerves Flashcards
In a patient with traumatic damage to the femoral nerve at the level of the inguinal ligament, why would sensation be preserved over the lateral thigh?
The lateral cutaneous nerve does not originate from the femoral nerve, so will be unaffected.
What are the nerve roots of the sciatic nerve?
L4-S3
What are the nerve roots of the obturator nerve and femoral nerve?
L2-L4
What are the nerve roots of the superior gluteal nerve?
L4, L5 and S1
What are the nerve roots of the inferior gluteal nerve?
L5, S1 and S2
What motor functions would be affected by damage to the femoral nerve?
Loss of hip flexion and knee extension
What sensory effects would you see if the femoral nerve is damaged?
Loss of sensation in anterior thigh and medial leg (saphenous stems from femoral)
What motor signs would you expect to see if the obturator nerve is damaged?
Loss of adduction of thigh
What sensory signs would you expect to see if the obturator nerve is damaged?
Loss of sensation inner thigh
What would you expect to see if the inferior gluteal nerve is damaged?
Loss of extension of hip
Buttock wasting
What motor functions would be compromised if the sciatic nerve is damaged?
Loss of all except adduction and flexion of thigh and extension of knee
What sensory problems would you see if the sciatic nerve is damaged?
Loss of sensation lateral leg and foot
What motor sign would you expect to see if the common fibular nerve is damaged?
Loss of extension of toes and foot (foot drop)
What sensory changes would you see if the common fibular nerve is damaged?
Lossof sensation over lateral lower leg and upper foot
What motor problems would you see if the tibial nerve was damaged?
Loss of plantar flexion, loss of flexion of toes and weakened inversion (tibialis anterior can still invert)
Name the artery that accompanies the sciatic nerve as it exits posterior to the piriformis muscle.
Inferior gluteal artery
If the sciatic nerve is damaged inferior to the point that it leaves the pelvis, will hip extension be present, absent or compromised?
Compromised - as gluteus maximus is mostly unaffected
Will knee flexion and dorsiflexion be present or absent after damage to the sciatic nerve?
Absent
What is the name given to nerve injury when axons distal to the injury undergo degeneration.
Wallerian degeneration
What is a traumatic neuroma?
A lesion that occurs after a nerve has been severed when there is poor alignment of the cut ends of the nerves.
A disordered proliferation of axons resulting in a tangled mass
Apart from a nodule, what is the commonest symptom associated with a neuroma?
Pain!
What is the most common mechanism of saphenous nerve injury?
Operation stripping of long saphenous vein - nerve accompanies vein
What symptom is present if the saphenous nerve is damaged?
Loss of sensation over medial leg
What sensory loss if the deep peroneal nerve is damaged?
1st web space
What sensory loss would you see if the superficial peroneal nerve is damaged?
Sensory loss over most of skin of dorsum of foot (not first web space) and anterolateral calf
What is the course of the gluteal nerves?
Leave pelvis via greater sciatic foramen.
Superior gluteal nerve passes superior to piriformis muscle and inferior gluteal nerve passes inferior to piriformis.
