|
Home / Health
Peroneal Neuropathy: Waiting for the Other Foot to Drop
By:Gary Cordingley, MD, PhD
A "foot-drop" is a medical term which--thankfully--does not mean that the foot suddenly disconnects from the leg. Rather, it means that when the leg is lifted from the ground, the foot droops downward at the ankle. The muscles that are supposed to prop up the foot have become so weakened that they cannot overcome gravity's downward pull. When people with this problem try to walk, they have to either hike the leg higher to clear their drooping toes or else risk tripping over them.
What is to blame for this inconvenient symptom? In truth, there are multiple possible causes, but one of the most common culprits is injury to a nerve-bundle in the leg known as the peroneal nerve. To understand how this nerve-bundle can get in trouble, a quick review of the bones of the leg is helpful. There is just one bone, a big one, that connects the hip to the knee, and that is the femur. There are two bones that connect the knee to the ankle. The tibia is the larger one and lies more to the inside, while the fibula is the thinner one and lies more to the outside. That's the extent of the bony anatomy we need to know.
The nerve-fibers constituting the peroneal nerve travel with the huge sciatic nerve that runs behind the femur from the buttock to the lower thigh. That's where the "common peroneal nerve" splits out from the pack and runs along the outside of the knee, tucking behind the head of the fibular bone (a knobby protrusion just beyond the knee) and then snaking around the neck of the fibula just below its head. The neck of the fibula forms the floor of the fibular tunnel that the common peroneal nerve must pass through. Within this tunnel the common peroneal nerve is particularly vulnerable to injury.
Also within this tunnel the common peroneal nerve splits into two branches, the "deep peroneal nerve" (farther from the leg's surface) and the "superficial peroneal nerve" (closer to the leg's surface). Because the two branches have different connections to muscles and skin, injury to one produces different impairments than are produced by injury to the other.
The deep peroneal nerve is responsible for cocking up the ankle and toes, so injury to this branch produces weakness or paralysis of the muscles responsible for these actions. There is just a tiny patch of skin, located between the big toe and the toe next to it, connected to the deep peroneal nerve, so damage to this branch produces numbness limited to this small area.
The superficial peroneal nerve, by contrast, is responsible for skin sensation on most of the outside of the calf and top of the foot, so these areas can become numb when the superficial peroneal nerve is injured. This branch is also responsible for lifting the outside edge of the foot, so this action is gone when the superficial peroneal nerve is not functioning properly.
Impairments due to injury of the common peroneal nerve (the parent of the two branches) are the sum of the impairments associated with each of the branches. So this means that the ankle and toes cannot cock upwards, the outside edge of the foot cannot lift, and there is numbness on the outside of the calf and top of the foot.
"Peroneal neuropathy" means impairment of the peroneal nerve. Peroneal neuropathies are the most common neuropathies (of the kind that affects just one nerve at a time) in the lower extremities. Investigators at the Louisiana State University Health Sciences Center recently collected a series of 318 patients with peroneal neuropathy who required surgery, while Italian researchers collected another 69 cases that included those who didn't need surgery. From these two tabulations of cases a good picture emerges of the more common causes of peroneal neuropathy.
Many were due to physical traumas. Some of the traumas were severe enough to break or dislocate bones, while others involved deep cuts in the soft tissues, and still others involved just a stretch or bruise. Another common cause was surgical operations. Some of the surgeries were to the nearby knee, but others were performed on more distant structures, like the hip, the abdomen or even the chest.
Many cases were due to excessive external pressure being applied to the nerve. This occurred in different ways. For example, in prolonged leg-crossing the knee of the bottom leg pushes steadily against the peroneal nerve of the crossing leg. Peroneal neuropathies seen in bedridden patients were presumably due to lying on the fibular tunnel for too long without a shift in position. Other patients had entrapment or pinching of the nerve within the fibular tunnel unrelated to external pressure.
A surprisingly large group of patients had peroneal neuropathy due to weight loss, also known as "slimmer's paralysis." More than one factor might have been at play in these cases, including lack of nutrients, pressure on the nerve, or both.
Researchers and clinicians find that in some people an apparently isolated peroneal neuropathy is actually the leading edge of a more widespread polyneuropathy. "Polyneuropathy" means that peripheral nerves are impaired in a more diffuse pattern--not just single nerves in single places. So in some cases of apparent peroneal neuropathy further investigations turn up polyneuropathy due to other causes, for example, diabetes, excessive alcohol consumption or genetic factors.
How are cases evaluated? The physician's evaluation starts with the time-honored methods of history-taking and physical examination. As part of the physical examination the doctor inventories which muscles are weak (and which are not) and maps out areas of numbness affecting the skin. Additional testing with electromyography and nerve conduction studies, which check on electrical functions of the muscles and nerves, often provides valuable information, including whether additional nerves are affected and how bad the impairments are.
How about treatment? Treatment varies according to what caused the peroneal neuropathy in the first place, but let's consider a typical case unrelated to severe trauma. Nonsurgical approaches are usually tried first, including avoidance of further pressure on the peroneal nerve, improved nutrition and supplementation of the diet with vitamins. A simple brace applied to the ankle improves walking. In many cases the nerve recovers without anything more drastic being done. But if these conservative treatments fail (and the peroneal neuropathy is not part of a more widespread polyneuropathy) then surgical exploration of the fibular tunnel is often indicated. If the nerve is pinched, then the surgeon frees up the nerve from whatever was pinching it.
(C) 2005 by Gary Cordingley
Digg
del.icio.us
Blink
Stumble
Spurl
Reddit
Netscape
Furl
Article keywords: peroneal, nerve, neuropathy, polyneuropathy, fibular tunnel, entrapment, pinch, foot drop, palsy
Article Source: http://www.articles2k.com
Gary Cordingley, MD, PhD, is a clinical neurologist, teacher and researcher who works in Athens, Ohio. For more health-related articles see his website at: www.cordingleyneurology.com
|
|
| Top Health Articles |
- 1). Collarbone Injury By : Frank Vanderlugt
The clavicle or “collar bone” connects the scapula bone in the shoulder to the sternum in your chest. It functions to hold the shoulder upward and backward.
Clavicle fractures are common bone injuries. A break in the clavicle bone is usually a closed fracture that normally takes approximately 6 weeks to heal in an adult, 4 weeks in a child. The injury rarely requires surgery.
|
- 2). The Hottest Hair Trends And The Sexiest Hairstyles For 2007 By :
Copyright 2006 David Maillie
Hair has become unequivocally important as it can literally make one look like a movie star or a has been from Hee Haw, which died out many years ago. It is big enough that it is a multi billion dollar industry and the average bill in a salon is approaching $100. In the big cities with a hot hairstylist like Jonathon in Beverly Hills prices can easily top $500 for a cut and style.
|
- 3). Muscle Imbalance And Chronic Injuries By : Jeff P. Anliker, LMT
Injuries can occur anywhere and at anytime, but the most prevalent place of occurrence is in the workplace. The reason for such a high rate of injury is that people spend 8-18 hours a day, 5-7 days a week performing unidirectional (one-way) movement patterns, causing an imbalance in the musculoskeletal system that results in the overuse and under use of certain muscle groups.
|
- 4). Why Whey Protein? By : Sandy Knoll
With all of the recent negative press given to body supplements, it makes good sense to be cautions about using different nutritional supplements as a part of your body building efforts.
Whey protein has been lauded as a safe, natural and simple supplement. It's use has become popular for those genuinely interested in good health through physical fitness and body building.
|
- 5). Autism and its Generated Behavioral and Mental Impairments By : Groshan Fabiola
Autism is a complex neurological disorder that dramatically affects people’s behaviors and social interactions. The disorder can be revealed in early childhood, by the age of 3. Although the first signs of autism can sometimes be identified in infants, the disorder is usually discovered at a later stage of life. Autistic children present a wide range of behavioral abnormalities, and they can be easily identified among normal children.
|
- 6). Why Asbestos Cancer Affects More Men? By : Alfred J.James
Who needs to be examined?
Individuals who have been exposed (or suspect they have been exposed) to asbestos fibers on the job or at home via a family contact should inform their physician of their exposure history and any symptoms. Asbestos fibers can be measured in urine, feces, mucus, or material rinsed out of the lungs.
A thorough physical examination, including a chest x-ray and lung function tests, may be recommended.
|
- 7). The Benefits of Martial Arts Training By : Clint Leung
As any martial arts practitioner will tell you, there are multiple benefits in martial arts training. Of course, the most obvious benefit is a knowledge of self defense which is one of the major reasons why the martial arts were developed in the first place. Knowing how to defend oneself and loved ones in a potentially dangerous situation is an asset in today’s world just as it was hundreds of years ago.
|
- 8). Study Says Obesity May Be Caused By Virus By : Rick Hendershot
In new study published this month, a research team claims to have found evidence that a contagious virus can contribute to obesity.
The team found that a specific human adenovirus Ad-37 seems to trigger obesity in chickens. Previous studies had linked other adenoviruses -- Ad-36 and Ad-5 -- to obesity in animals.
These and other adenoviruses cause colds and other common illnesses in people.
|
- 9). How Long Will It Take To Gain Muscles| Build Muscle Mass By : Chris Chew
There are many factors to consider when you want to know how long will it take for you to gain and build muscle mass. Questions like are you eating enough and the right nutrients to accelerate muscle growth, are you exercising correctly and regularly and do you have the genes for quick muscle growth need to be addressed.
In this article, we shall discuss whether you have the genetic make up to gain and build muscles quickly.
|
- 10). Breathe Easy: Some Asthma Relief Tips By : Nick Carter
Asthma is the seventh-ranked chronic health condition in the United States and the leading chronic illness of children. It is a chronic inflammatory disease that makes airways (bronchial tubes) particularly sensitive to irritants.
During an asthma attack, tightening of the smooth muscles around the bronchial tubes causes them to become inflamed, narrow inside, and produce excess mucus.
|
| New Health Articles |
- 1). How To Break An Addiction By : John Morris
You need to evaluate the problem and find what triggers your addicts and what specific need it is using. Once you have determined that, you can begin breaking yourself of the habit one step at a time...
|
|
|
|
|
|
|
- 5). Make Your Heart More Healthy By : Dan Sherman
Does it seem like there are more health risks these days than there were in the past? Well, the plain and simple truth is, there are. Now, more than ever, people around the globe grapple with various heath afflictions.
|
- 6). The Best Ways To Quit Cigarette Smoking By : Jonty Smith
The author packed in his 40-a-day habit within a few hours. He did it quickly, easily and painlessly. Why then do so many other smokers struggle to quit? In this article, the author explains the best ways to quit cigarette smoking, and why many of the established methods are counter-productive.
|
- 7). Can Chocolate Really Kill Your Dog By : Gregg Hall
We have all heard this all of our lives but how big a threat is it really? Is it life threatening or will it just make him sick? How much chocolate does the animal have to eat for it to cause a negative reaction?
|
- 8). The Attraction Of Magnetic Therapy By : John Morris
Magnetic therapy is an alternative treatment for common ailments. The most commonly treated ailments for that magnetic therapy is used for are arthritis, pain, inflammation, muscle tension, migraines, tumors, asthma, allergies, diabetes and many other joints or healing complaints...
|
|
|
|
|
|
|
