Here, we’ll take a look at
femoral nerve, a motor deficit.
And by this,
we are referring to the iliopsoas
and quadriceps weakness,
down obviously in the leg.
And so therefore, there’s inability
to flex the hip or the knee.
Femoral nerve, motor deficit.
And we have what’s known
as meralgia parasthetica.
And with meralgia parasthetica,
it’s a compression of lateral femoral
cutaneous nerve of the thigh.
And therefore, the patient
now is complaining of
lateral thigh numbness and burning.
This is then called
Please take a moment and identify
femoral nerve in this schematic.
Let’s take a look at what may
happen when you have mononeuropathy
of the common peroneal nerve.
Let’s take a moment and identify the head
of the fibula, common site of injury.
And we’ll do the same things as we’ve been
doing with all of the mononeuropathies
and we’ll begin by looking
at clinical features.
This time, you’ll have foot drop
and occasional leg, maybe perhaps the top
of the foot in which there’s numbness.
Risk factors: Diabetes, alcoholism, HIV.
I'll run through this quickly
because it is common risk factors
for any type of mononeuropathy.
However, now we have tight cast or splint
placement and that will be more specific.
And leg crossing and leaning
is a common issue actually.
Those individuals who cross their
legs often may actually have
common peroneal nerve
mononeuropathy or injury.
Physical exam: Patient unable
to pull foot or toes up.
So unable to properly what?
With the common peroneal nerve, it is
important that you’re able to localize
exactly as to where the
lesion is taking place.
The last time you’ve done this
before was your radial nerve,
where there also localization
is extremely important.
So spend some time and make sure
that you’re able to properly locate
where the lesion took place
to the common peroneal nerve.
You check the peroneus
longus, by foot eversion,
tibialis anterior by foot dorsiflexion and
sensation over the dorsum of the foot.
Now, if there’s peroneus longus
plus a tibialis anterior involved
and you have decreased
dorsum foot sensation,
you will be able to localize the
lesion to the common peroneal nerve
above the fibular head.
If the peroneus longus is involved and you
have decreased dorsum foot sensation,
but the tibilias
anterior is spared,
then you know that the damage is
taking place below the fibular head.
If the peroneus longus is spared and the
dorsum foot sensation is preserved,
but the tibialis
then you know that this
is a deep peroneal lesion
and this will be below
the fibular head.
We have a couple of things
here, the common peroneal,
and the deep peroneal.
It will behoove you to quickly take a
look at the schematic that I’ve shown you
with different branches
of the common peroneal.
Let’s move on.
Symptomatic treatment is brace.
In other words, plastics,
to maintain your feet in dorsal
flexion and to then prevent falls.
Also help preventing tightening
of your Achilles tendon
which will make recovery
Oh, look where we are.
If accompanied by bowel/bladder symptoms,
it could be caused by cauda equina lesions.
So now you start looking at the
spinal cord, is that clear?
If you suspect ALS,
then obviously with ALS, you have
other muscles that are involved
and you have
fasciculations, won’t you?
Remember that you have both upper and
lower motor neuron lesions with ALS.
and this then causes weakness
and look for that wasted leg
and bilateral foot drop if you’re
thinking about myotonic dystrophy,
which is rare, but
nonetheless a differential.