Welcome to the Podiatry Arena forums

You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

  1. Everything that you are ever going to want to know about running shoes: Running Shoes Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
  2. Have you considered the Critical Thinking and Skeptical Boot Camp, for taking it to the next level? See here for more.
    Dismiss Notice
  3. Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
Dismiss Notice
Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
Dismiss Notice
Have you liked us on Facebook to get our updates? Please do. Click here for our Facebook page.
Dismiss Notice
Do you get the weekly newsletter that Podiatry Arena sends out to update everybody? If not, click here to organise this.

Deep peroneal dermatome - numbness

Discussion in 'General Issues and Discussion Forum' started by Asher, Feb 20, 2008.

  1. Asher

    Asher Well-Known Member

    Members do not see these Ads. Sign Up.
    Hi there,

    I have a patient who experiences constant semi-numbness (protective sensation intact) at the deep peroneal dermatome - the area of the 1st and 2nd toes and the interdigital area. This has been the case for a few months.

    Other than being concerned that it might be a sign that she has diabetes, it does not concern her. It does not get painful. Shoes do not aggravate it, even if shoes do get a bit tight on the dorsum of the foot (eg: do laces up too tight), it does not change the degree of numbness.

    I have seen a few dorsal nerve irritations which either respond to reduced pressure or cortisone injection (done by the surgeon) but they are always painful and aggravated by shoe pressure and I can reproduce the pain with palpation. This case satisfies none of the above.

    She has a 'bad spine lower back'. On questioning, some time ago, there was a tingling / creeping sensation down the leg which was very mild and only very short term - patient a bit vague about it.

    Any ideas? Thanks in advance.

  2. Ella Hurrell

    Ella Hurrell Active Member

    Hi Rebecca

    I might be inclined to get an ultrasound or other scan to check for local causes ie.neuroma etc, but if that comes back clear, it could be referred from the mystery 'bad back'! How come patients are always vague on the important stuff?!:bang: It might be worth getting some more info about the actual diagnosis of the back issue from the GP?

    Let us know if you find out any more.

  3. pgcarter

    pgcarter Well-Known Member

    Can you be more specific about the area effected? The sensory nerves for the interdigital web space of 1-2 are deep peroneal but the dorsal surfaces of the toes are superficial peroneal nerves.....not the same pathway from the cross over at the proximal fibula......it may be possible to learn some more about this by closer examination of details. Obviously if only some distal nerves are having parasthesia...then it's not effecting all of the peripheral nerves in the same way (not likely to be diabetes)...(pressure on dorsum of foot is not going to effect innervation to 1st webb)...pressure on nerve roots at the spine is again a different thing and with reference to a text you may be able to determine if the problems are all coming from one or two intervertebral nerve roots or not?
    Never easy to sort all that stuff out and short of referral to a neurologist you're not likely to get much more specific effort I don't think.
    reqards Phill
  4. Asher

    Asher Well-Known Member

    Thanks Ella and Phill

    Phill, I have had a look at my anatomy book and confirmed the course of the deep peroneal nerve and its dermotome. My book shows it innervates half of the dorsal surface of each toe plus the interdigital space - I had my patient draw on her foot the boundries of the affected area and that is almost exactly what she drew - so I'm pretty confident its the deep peroneal. Thanks for your advice.

    I assured her it wasn't diabetes. My query is, whether local or proximal casue,if its not annoying her, do you necessarily have to do anything about it? Can it lead to anything nasty in the longer term?

    I will enquire about the back problem further with the GP (who referred to me with no details). And I may get an ultrasound. Thanks for your help Phill and Ella.


  5. Rebecca:

    The most common causes of deep peroneal nerve symptoms (you are right, the deep peroneal nerve supplies sensory function to the dorsal aspect of the first web space) are shoe irritation or trauma (e.g. dropping something on foot). If it is not painful, then I would not be too concerned about it. The deep peroneal nerve may get entrapment neuropathies at other points along its course. I have attached an article detailing an entrapment neuropathy of the deep peroneal nerve caused by an exostosis.

    Good luck and keep us informed of her progress.
  6. Asher

    Asher Well-Known Member

    Thanks for that paper Kevin and for the Drop Foot paper in the Awkward Gait thread.

    A few questions:

    If one suspects a spinal level aetiology, will there usually be symptoms in between the spine and foot?

    What’s the difference between nerve entrapment and nerve compression? I have read that compression is pressure from an underlying bony prominence and nerve entrapment is a long-term compression that occurs over a joint and the nerve is subject to inflammation and swelling. Is this an acceptable differentiation or are the two words used interchangeably?
    Is a positive Tinel’s sign a definitive test for diagnosis of a nerve entrapment on the dorsum of the foot?

    There won’t always be motor and sensory components to symptoms will there, it just depends on the particular nerve fibres affected?

    As well as the anterior leg comparment muscles, the deep peroneal nerve innervates the extensor digitorum brevis (as well as extensor hallucis brevis and sometimes the second and third dorsal interosseous muscles) – does anyone use this fact to diagnose deep peroneal nerve pathology?

    Many thanks

  7. Rebecca:

    Let me try to answer your questions:

    1. Spinal level pathology will generally cause symptoms/signs that correspond to the nerve root affected, which may or may not be between the spine and foot. These symptoms/signs may either be sensory or motor in nature. Type the term radiculopathy into a search engine and you will have at least a day's worth of reading.

    2. Nerve entrapment would generally indicate that the nerve is being compressed circumferentially by scar tissue or a tight soft tissue structure. Nerve compression would generally indicate that the nerve is being compressed either internally or externally on only one side of the nerve. However, I have also heard the terms used interchangeably so it is important to know that in either case, a nerve injury has occurred due to compression of the nerve.

    3. The Tinel's sign is a good test for nerve injury. I use it nearly daily in my practice to determine the specific anatomical area, extent and magnitude of nerve injury in the foot/lower extremity.

    4. I haven't seen an injury to the deep peroneal nerve affect the extensor digitorum brevis, but it would be hard to isolate out this muscle from the other digital extensors with muscle testing.

    The deep peroneal nerve is quite easily palpated along the dorsal midfoot in nearly all individuals and will be very sensitive to light touch if injured. Deep peroneal nerve injury may also cause partial to complete numbness, burning pains, tingling sensations, and/or hypersensitivy in the dorsal aspect of the first intermetatarsal and first web space. Most of the deep peroneal nerve injuries I see are from people hurting themselves by having something drop onto or crush their foot.

    Hope this helps.
  8. Scorpio622

    Scorpio622 Active Member


    What you describe is not a dermatome but rather a "peripheral nerve field", "peripheral nerve distribution", or "cutaneous nerve distribution". The term dermatome suggests radiculopathy and indicates the entire area of skin innervated by a spinal root and not a peripheral nerve.

    Use the term again, and I will have to arrest you :butcher:

    Captain, Podiatric Language Police
  9. Asher

    Asher Well-Known Member

    That's fantastic, thanks for setting me straight Nick and Kevin!


Share This Page