Leg Weakness – Causes and Treatment

Leg weakness is a serious symptom which is commonly ignored by many people. Leg weakness is highly based on ones own perception, so many people may not even realize that they have leg weakness. However, for practical purposes it is the first sign of paralysis because of nerve compression in the lower back. Leg weakness is frequently accompanied by loss of touch sensation and shooting pain, which generally come before the leg weakness. Thus, loss of sensation or shooting pain can be taken as an alarming signals, which tell us that leg weakness is on its way. Hence, it should be taken very seriously and any prompt medical help should be sought. This is especially important for people having low back problems, who have a greater chance of getting leg weakness.

What is leg weakness ?

Leg weakness should not be confused with tiredness or a heavy feeling that one gets after a long day of work. It is the weakened strength of the leg muscles, which is manifested by inability to do certain movements with the foot or leg. Leg weakness should also not be confused with a muscle cramps or arthritis which cause a painful inability to move the foot or leg. Leg weakness also interferes with walking especially when it is involving the foot muscles. This is known as foot drop, in which a person unable to lift the foot upwards.

How does leg weakness occur ?

The leg is supplied by nerves which come out of the spinal cord and back bone in the lower part of the back. These nerves travel all the way from the lower back to the various parts of the leg, imparting it touch sensation and movement. The vertebrae in the lower part of the back are a common site of diseases like slip disc (slipping of cartilage intervertebral disc (Picture 1, 2) which normally lies between two vertebrae causing compression of nerves or spinal cord), sciatica (compression of a nerve bundle as it comes out of the hip bones), and leprosy (fibrosis of superficial nerves near the skin). The nerve damage caused by these diseases results in abnormal functioning of the parts supplied by the nerves (generally muscles and touch sensation). Consequently, when a large part of the leg looses its nerve supply, like a major muscle, it makes the person unable to do the movement performed by this part (muscle) or makes the part insensitive to touch.

Picture 1: Intervertebral disc, top view
(source: Chiro Org Images)

Picture 2: Intervertebral disc, side view
(source: Chiro Org Images)

Why is leg weakness an emergency ?

Nerve damage is almost always permanent as nerve tissue does not grow back easily. One can only prevent further damage by identifying its cause and taking treatment, but the damaged nerve can not be repaired. There is a window period of a few days between getting leg weakness and the nerve being permanently damaged. Thus, if leg weakness is treated during this period, the permanent damage to nerves can be avoided and leg movements can come back. So it is very important to seek medical attention and perform the diagnostic tests early, to complete treatment within this window period.

Diagnosis of Leg weakness

Leg weakness most commonly arises from nerve compression in the lower back. Hence, pain in the lower back region should not be ignored, especially if it is longstanding. The shooting pain, which travels from the lower back to the knee or the ankle, is because of the irritation of the nerves caused by compression. This is also called sciatica because the nerve coming out of the hip bone is called the sciatic nerve, which divides into smaller nerves which supply the leg muscles and also provide touch sensation.
The initial evaluation consists of evaluation of the leg muscles by a doctor or a physiotherapist. The doctor would ask you to do several simple movements and measure the strength of your movements by opposing the movement with his hand. The touch sensation is also tested with a cotton wisp or a pin to find out the exact region of sensory loss.
This helps in locating the probable site of the nerve compression so that further tests can be directed towards that region.
The common diagnostic tests employed for investigation of causes of leg weakness are:

Picture 3: Spondylolisthesis on X-ray
(source: Wikimedia)

  1. X-rays of lower back, which rule out bony abnormalities like fractures or spondylolisthesis (forward or backward slipping of a vertebra)(Picture 3). This is the primary investigation for all causes and is especially important when one has had a traumatic incident like a fall or a road accident.
  2. MRI helps in diagnosis of injuries and abnormalities like slip disc, intervertebral disc protrusion, nerve compression, and so on. Soft tissues which cannot be seen on x-rays can be seen on MRI so the causes related to them can be accurately diagnosed.
  3. Nerve conduction studies are used in diseases, which are difficult to visualize on X-ray or MRI like leprosy, syphilis, etc., and which are confined to the nerves. In this test, small electrodes are stuck to the different parts of the body and measurements are made of the electrical activity of the nerves of that part.

After these investigations and the physical examination, leg weakness can be attributed to compression of spinal cord (Picture 4), compression of spinal nerve (Picture 5 ), or local nerve disease.

Picture 4: Spinal Cord Compression
(source: Wikimedia)

Picture 5: Spinal nerve compression
(source: Wikimedia)

Compression of spinal nerve or spinal cord is mostly due to intervertebral disc protrusion. However, some other causes for the same are spinal tumor, sciatica, dislocation of vertebra (spondylolisthesis), fracture of vertebra, and spinal stenosis.

Local nerve diseases are leprosy, syphilis, nerve cut injury, or neurofibroma.

Treatment of Leg weakness

Leg weakness due to local nerve disease is treated as per the disease condition. Most of these diseases are treated with medicines and do not require surgery. However, the medicines have to be continued for many months, or sometimes even a couple of years.

Leg weakness caused by spinal cord or nerve compression are treated by surgery more often than by medicines. The diseases like sciatica and fracture of vertebra are generally treated with bed rest and painkillers for a period of 6 weeks. This is followed by gradual exercises and physical therapy which strengthen the muscles. The other medicines which are helpful in reducing the pain are muscle relaxants and neurovitamins. As long as the treatment program is religiously followed there are no complications. However, if not followed, one may end up being a paraplegic for life.

The surgery for spinal tumor or intervertebral disc protrusion should be taken only when leg weakness or loss of sensation is present. A person also has to wear an orthosis (a belt for the back which gives support and restricts some movement)(Picture 6) after surgery for a period of 6-8 months until the bones and muscles regain their strength. Simple low back pain or shooting pain should not be taken as an alarming sign for surgery. They should only be pointers towards a medical evaluation for leg weakness.

Picture 6: Orthosis for lower back
(source: Wikimedia)

The surgery of spinal cord or vertebral column is not at all risk-free. There are chances that one may end up in paralysis after the surgery. It is also expected from the patient in writing that one is aware of this disastrous consequence and is still ready for the surgery. In the presence of leg weakness, surgery is a logical choice as one is eventually going to end up in paralysis without the surgery. But in the absence of leg weakness, there is still time and one can try medicines and physical therapy for improvement.

Related Articles:

Sciatic Nerve Pain – Causes and Symptoms

Leg Numbness, Tingling Feet and Toes

About Dr Gauresh (69 Articles)
An orthopedic surgeon trained in JJ Group of Hospitals and Grant Medical College. I have worked in this field for the past 3 years and have significant clinical experience to guide students and patients on any topic in orthopedics.

Please note that any information or feedback on this website is not intended to replace a consultation with a health care professional and will not constitute a medical diagnosis. By using this website and the comment service you agree to abide by the comment terms and conditions as outlined on this page

  • chenoaspirit

    my symptoms began one evening when I leaned back on the couch and a very intense sharp stabbing pain in my left buttock shot down my left leg. It was the worst pain Ive ever had in my life, I could not move at all for 3 days, could not bear weight at all. Even my husband carrying me was unbearable. Finally I borrowed a walker and stood with it, so that I could stand without bearing weight on that left leg. It felt like everything in that leg was stretched out, it hurt and burnt, but that led the way to being able to walk again. Now that leg remains extremely weak. This has been an issue now for 4 weeks. I am unable to walk up or down steps/stairs. I can not push up from a squatting position at all with this leg. If I forget and try to walk fast, I fall. Ive fallen several times due to the leg “giving out”. My right leg is fine. Ive had MRIs of my back, all with different readings, which confuses me. I have bulging discs from L2/3 to L5/S1 according to one MRI, only at L3/4 and L4/5 on another MRI, one year ago a MRI showed multi-level bulges, no herniations, with mild/moderate neural foraminal narrowing, but Ive had this for several years. Three weeks ago, I had no reflexes in my knee or ankle at all, now they are weak and remain weak. My doctors seem unconcerned. But this is not improving and I live in a town with minimal options for healthcare (very small town). Im going to PT, which is making no difference. The PTA there scared me, saying that I may lose complete use of my leg if nothing is done, but the PT says the opposite and also seems unconcerned. I AM VERY CONCERNED. I have multi-level damage in my c-spine that required surgery, T-spine is normal. I dont know what is going on with my leg but I have low back pain too. I am unable to walk for any distance or stand for long. I have severe migraines too, Im suspecting are related to my C-spine damage. I had a EMG done, but the doctor was really unsure where to place needles, pulling them out, shoving them back in, moving them, wiggling them, then moving them again before performing each shock. it was “normal” and I do not understand how. My knee cap feels numb as well. Any idea what it could be, or anything I could suggest to one of my doctors.

  • Hi Chenoaspirit. From what you describe it seems to be a herniation of one of the discs (lumbar and/or sacral) causing the vertebrae to now press on the nerve running down to your leg. It is a concern if your symptoms are worsening as it could mean that the underlying condition is getting progressively worse over time. The current treatment regimen is obviously not working and alternatives may have to be considered, possibly even surgery.

    We cannot comment on whether the approach of your doctor(s) is correct or not. Neither can we advise you on what to tell your doctor to do. This commenting service is simply intended to guide patients, but we can neither diagnose or advise on treatment.

    If you are concerned about the level of care that you are receiving then you should seek a second opinion. Your geographical location is obviously a complication in the matter but you should be seeing an orthopedist (orthopedic specialist) who may refer you to a neurologist if necessary.

    Consider seeing a specialist which may mean going out of town. Delaying further medical attention on this matter could lead to further complications in the future.

  • Darin Taylor

    I started having issues with muscle weakness and development in my right leg after a bone debridement surgery on my right hip. I went through several months of physical therapy and though that all was OK; then about a month after therapy I noticed that my right leg looked smaller in diameter to my left leg and I didn’t have the strength to raise up on my tip toes or push myself up from a seated position using my right leg. I have been through numerous muscle and nerve conduction test along with MRI’s, and each time the doctors tell me that nothing is wrong. There has to be a physical issue that hasn’t been addressed to solve this problem. This has been going on for more than 2 years. If anybody has any ideas that I can pass on to my doctor, I would really appreciate it.

  • John Gibbs

    Hello,
    In July I had fusionsurgery on two discs in my neck. I still have nerve sensations in my legs and numbness in my arms and fingers. I also have extreme weakness in my legs and do not walk normally. I have been put on gabapentin which has helped a little bit with the sensations in my legs but I’m really concerned about the weakness and I still have numbness in my arms and fingers. Are there any medications or exercises I should be trying to help regain the weakness in my legs. I’m 46 years old and miss doing physical activities like racquetball and jogging and I can no longer do.

  • Hi John. Continuing paresthesia (abnormal sensations) and some weakness is not uncommon after spinal fusion surgery. This does not mean that it is normal post-operatively but it does happen in some cases. However, it should not be worse than it was before the surgery. You should go back to the neurosurgeon who did the procedure and inform him about it. He should in turn refer you to a physical therapist to assist with recovery where/if possible. If you are not finding the level of attention that you should be getting from the specialist then it may be time to seek a second opinion from another specialist.

  • syaheera

    Hi.

    Syaheera here..for past 5 months until nw im having a sensation which i suddenly feel like weakness in leg and imbalance which i feel like everytg moving around me especially when i went anywhere i feel like everytg moving and cannot be stabelized..can i knw whyis the reason maybe

  • syaheera

    Syaheera here..for past 5 months until nw im having a sensation which i suddenly feel like weakness in leg and imbalance which i feel like everytg moving around me especially when i went anywhere i feel like everytg moving and cannot be stabelized..can i knw whyis the reason maybe

  • Hi Syaheera. As you can see there are many possible causes of leg weakness. However, in your case the question is whether there is actual leg weakness or whether you are just feeling this without any weakness. Even if you have fallen when you had this feeling, it may still not be leg weakness. It could be problems with your inner ear where some of the structures are responsible for balance. It could even be a momentary loss of adequate blood supply to the brain as is seen with TIAs (transient ischemic attacks) which precede strokes. Of course, it could be a problem with the legs itself, either the muscles or the nerves supplying it. You need to consult with a doctor who can conduct further investigations before reaching a final diagnosis.

  • syaheera

    thank you for the information..just wants to knw the exact doctor to consult with is ENT specialist or any other doctor ?

  • Hi Syaheera. It is advisable to first consult with your GP and then ask for a referral. Given the information you had previously provided you may need to see a neurologist. However, if your GP has other concerns after assessing you then he/she may advise on another type of specialist first.

  • syaheera

    hi,thank for the feedback ..just wanted to know i have visit a clinic which they provides a lot types
    of vitamins..

  • Syaheera, you should speak to your doctor or a nutritionist if you are looking at different types of nutritional supplements. I’m not sure what types of clinics you may have in your country that offers many types of vitamins.

  • RSG

    My friend accidentally hit me on the left side of the face and ear two weeks back. Since then, the left side of my face beneath the forehead feels mildly numb. And when I walk for a bit, my left leg feels weak. I also have mild pain and heaviness at the back of the neck and head. I had MRIs of the brain and cervical spine and those were normal. But the symptoms persist. Will be really grateful if you can provide an idea what might be the underlying cause for these symptoms and how they can be treated. Thanks in advance.

  • Hi RSG. As you have said the MRI is clear so it is quite perplexing as to why these symptoms may be persisting. Your symptoms seem to be due to some nerve-related condition. You should be consulting with a neurologist if you are not doing so already. Trying to isolate the underlying cause for these symptoms through an online platform can be difficult and we would be guessing. Best to speak to a doctor directly.

  • Khristine Marie Abella

    HI good day!
    I just want to ask about numbness of the two legs of my father., it occurs every once a month, no more other symptoms except no strength of his both legs, he even cant stand by his own but after two to three days it suddenly bring backs his strength even without any medication
    .I badly needed your suggestion.,thank you very much

  • Mario

    My right leg is getting weak and smaller. That made my back in desorder when I walk or stand and feel hurt
    What the solution please?

  • Hi Khristine. There are several conditions that can cause both numbness and muscle weakness of the legs but it is strange that it occurring on its own every few days without precipitating factors, like strenuous activity and so on. Since both legs are affected simultaneously it is possible that the problem likes at the lower back where the nerves to the legs emerge from the spinal cord. He should speak to his family doctor about it and possibly see a specialist for further investigation before it worsens and leads to complications.

  • christopher

    Hi dr i was diagnozed with disnia few months ago now a week ago i have pain in both legs limping when i walk

  • Richard

    Hello Richard here and i am 23 yeara old. About a month ago, I started noticing some mild vibrations all over my body, not long after, I noticed tingling sensations all over my legs and there was a change in its feeling. They started getting weaker and about two weaks later the weakness got worse on the left legs. It reliefs me little then it gets stiff again. I am unable to lift the left legs up and I find it difficult to climb stairs or walk properly. The right leg although still acting normal also tingles and the feeling when touched is abnormal still and lately the weakness is moving towards the left leg. I can still feel the legs but the toes are sort of stiff and functionless, in addition I also get this mild pain and stiffness on my back and chest. Although I am admitted already at the hospital for 5 days now, it’s difficult adjusting. I want to know if I still have hope that it will get better.

  • HI Richard. Since you are in hospital at the moment, your doctors will run a series of tests to confirm the underlying cause. We cannot advise you on the prognosis as each case is individual and it also depends on what the final diagnosis is. Your doctor or doctors will be able to advise you further. Fortunately you are under medical care at the moment. Do not worry too much about it until your doctors confirm the diagnosis. All the best!