Mononeuropathy - Foot Drop - Common Peroneal Nerve (L4, L5, S1)

 

Thank you for asking me Harry who presented with foot drop.

 

The salient findings on examination were a high-steppage gait with a right/left foot drop with associated weakness of eversion, but preserved ankle inversion and ankle jerk, with a sensory deficit over the lateral calf and dorsum of the foot, which is consistent with a common peroneal nerve palsy.

 

In further detail...

 

On inspection the patient was comfortable and did / did not have any gait aids. There were/were not any shoe or ankle supports.

 

The gait was high stepping (due to foot drop from distal motor neuropathy). The patient could walk heel to toe, suggesting the absence of a cerebellar pathology. The patient could walk on their toes (S1), but not their heels (foot drop, L4 or L5). Romberg’s sign was negative (eyes closed - posterior columns, eyes open - cerebellar).

 

There were/were no scars on the back.

 

On inspection of the legs, there was a scar over the neck of the right fibula. There was wasting over the anterolateral compartment of the right calf.

 

There was not muscle tenderness. Tone was normal in the knee and ankle, and there was/was not clonus. There was not an enlarged common peroneal nerve (CMT).

 

There was weakness of ankle dorsiflexion and eversion. Plantarflexion and ankle inversion was spared.

 

Reflexes were normal in the knee and ankle. Plantar response was downgoing/inadequately assessed due to withdrawal.

 

Coordination was normal on heel-shin, toe-finger and foot tapping assessment.

 

Sensation was reduced asymmetrical over the lateral calf and dorsum of the foot, consistent with the common peroneal nerve distribution.

 

In summary this patient has a foot drop, likely secondary to a common peroneal nerve lesion.

 

Differentials include:

• L5 nerve root lesion - however inversion would be affected, and the sensory deficit does not fit

• Sciatic nerve palsy - however, plantarflexion and inversion would be impaired, and the sensory deficit does not fit

• Lumbosacral plexus lesion

• A peripheral motor neuropathy

• Motor neuron disease - however, there should be no sensory deficits

• Distal myopathy

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Mononeuropathy - Foot Drop - L5 nerve root lesion

​

Thank you for asking me Harry who presented with foot drop.

 

The salient findings on examination were a high-steppage gait with a right/left foot drop with associated weakness of ankle eversion, ankle inversion and hip abduction, but preserved plantarflexion and ankle jerk, with a sensory deficit over the dorsum of the foot and lateral calf extending up to the lateral thigh, which is consistent with a L5 nerve root palsy.

 

In further detail...

 

On inspection the patient was comfortable and did / did not have any gait aids. There were/were not any shoe or ankle supports.

 

The gait was high stepping (due to foot drop from distal motor neuropathy). The patient could walk heel to toe, suggesting the absence of a cerebellar pathology. The patient could walk on their toes (S1), but not their heels (foot drop, L4 or L5). Romberg’s sign was negative (eyes closed - posterior columns, eyes open - cerebellar).

 

There were/were no scars on the back.

 

On inspection of the legs, there were/were not surgical scars. There was/was not wasting

 

There was not muscle tenderness. Tone was normal in the knee and ankle, and there was/was not clonus. There was not an enlarged common peroneal nerve (CMT).

 

There was weakness of hip abduction, ankle dorsiflexion, eversion and inversion. Plantarflexion was spared.

 

Reflexes were normal in the knee and ankle. Plantar response was downgoing/inadequately assessed due to withdrawal.

 

Coordination was normal on heel-shin, toe-finger and foot tapping assessment.

 

Sensation was reduced asymmetrical in a dermatomal distribution over the dorsum of the foot and lateral calf extending up to the thigh, consistent with the L5 distribution.

 

In summary this patient has a foot drop, likely secondary to a L5 lesion.

 

Differentials include:

• Common peroneal - however inversion would be spared, and the sensory deficit does not fit

• Sciatic nerve palsy - however, plantarflexion and inversion would be impaired, and the sensory deficit does not fit

• Lumbosacral plexus lesion

• A peripheral motor neuropathy

• Motor neuron disease - however, there should be no sensory deficits

• Distal myopathy

​

Mononeuropathy - Foot Drop - Sciatic Nerve Lesion

​

Thank you for asking me Harry who presented with foot drop.

 

The salient findings on examination were a high-steppage gait with a right/left foot drop with associated weakness of knee flexion, plantarflexion, ankle eversion, ankle inversion, with loss of the ankle jerk and plantar response (but preserved knee reflex), with a sensory deficit over the posterior thigh and below the knee, which is consistent with a sciatic nerve lesion.