Foot numbness can be described as tingling or feeling as though the foot has fallen asleep. Reasons for tingling in the feet can range from a simple muscle issue to a far more serious metabolic issue or from nutrition to physical compression on the nerve.
Nerve tissue runs from the spinal cord to the feet, making the body aware of temperature, touch and balance. These nerves usually run by and supply information to all of the joints, muscles and skin along the way. Water retention and swelling or more commonly, any ligament, tendon, or muscle tissue along its path can entrap or compress the nerve. When a nerve is entrapped, it can cause pain, tingling or muscle weakness further down the line. Common places in the lower extremities for nerve entrapment are the buttocks and groin, near the lateral knee and in the tarsal tunnel of the ankle, according to Medscape.com.
In between the vertebrae of the back are round discs, which act as shock absorbers and allow spinal movement. These discs are made of tough cartilage on the outside and a softer middle. Wear and tear or trauma can cause a disc to rupture, tear, bulge or herniate. Injuries to a disc may cause pain because it may press on tissues and nerves near the spine. The spinal cord and nerve roots exiting the spine are the most likely tissues to be pressed upon. When those nerves are compressed or irritated, it can cause numbness, tingling, sharp stabbing pain or muscle weakness in one or more areas of the thighs, legs and feet.
Arthritis and Stenosis
Arthritis is an inflammatory process of the bone, which can cause spurring, or bony outgrowths, around the bone. The inflammation alone can cause pain, but sometimes these bony growths can narrow the spinal canal, a condition called spinal stenosis. This puts pressure on the spinal cord or spinal nerves. Also, the spurring can push directly into a nerve, causing similar symptoms to that of a disc herniation.
Diabetes occurs when the pancreas does not produce enough insulin. Without the insulin, glucose, the body's fuel source, cannot enter the cells. Excessive glucose in the blood stream causes a range of symptoms, including tingling in the hands and feet. The National Institutes of Health states uncontrolled diabetes and people with other health conditions such as high cholesterol and blood pressure are more likely to have nerve damage, but it can strike anyone with diabetes at anytime. Without proper management of diabetes, this nerve damage can lead to further injury and loss of toes or the whole foot.
Many nutrients aid in healthy nerve function and growth. Deficiencies can lead to loss of feeling or pain in the extremities. Vitamins B12 and other B vitamins are necessary for healthy nerve function, according to the University of Chicago Center for Peripheral Neuropathy. Excessive alcohol use can strip the body of these nutrients, leading to permanent nerve damage and irritation. Additionally, the March 2007 issue of "Revue Neurologique" states that the use of nitric acid in anesthesia can cause a loss of B12 and lead to nerve alterations.
- National Institutes of Health: Diabetic Neuropathies: The Nerve Damage of Diabetes
- Medscape: Nerve Entrapment Syndromes
- Unversity of Chicago Center for Peripheral Neuropathy: Alcoholic Neuropathy
- "Revue Neurologique"; Nitric-Oxide Triggered Neurological Disorders in Subjects With Vitamin B12 Deficiency