Your body has two nervous systems: the central nervous system and the peripheral nervous system. Your central nervous system is composed of your brain and spinal cord, and your peripheral nervous system includes the nerves that supply sensation to the rest of your body, including the extremities. Your circulatory system is also responsible for providing oxygen and sensation to your extremities. Numbness in your big toe usually occurs as a result of abnormalities in your peripheral nervous system or circulatory system.
To make healthy red blood cells, your body requires vitamin B12 to be present in adequate amounts. Without enough B12, the production of red blood cells diminishes, which leads to a condition called pernicious anemia. Vitamin B12 may not be available to make red blood cells for a variety of reasons. These reasons include lack of adequate B12 in your diet and malabsorption of B12 by your body because of medical conditions, according to the National Heart Lung and Blood Institute. The most common symptoms of pernicious anemia are fatigue, weakness and shortness of breath. Because vitamin B12 is responsible for proper nerve function, deficiencies may also lead to neural damage. This results in abnormal sensations, such as tingling and numbness in the big toe. Pernicious anemia is usually treatable with a lifetime of B12 injections.
The sciatic nerve is a long nerve that begins in the spine and runs through the buttock and down the length of the leg. The sciatic nerve is responsible for muscle control in the leg and provides sensation to the thigh, lower portion of the leg and foot. Sciatica is the name for a symptom that occurs when pressure is on the sciatic nerve or the nerve is damaged. Damage or pressure can occur as a result of a slipped disk, degenerative disk disease, pelvic injury or tumors, according to MedlinePlus. Sciatica may cause pain in the back, buttock and leg, as well as weakness and numbness in the leg, hip, foot and toes. Because sciatica is a symptom of another condition, treatment focuses on correcting the underlying medical condition.
Peripheral Artery Disease
The peripheral arteries are the blood vessels that supply the limbs and extremities with blood from the heart. Peripheral artery disease is a condition characterized by narrowed peripheral arteries due to the accumulation of plaque on the arterial walls. The accumulation of plaque is referred to as atherosclerosis. When the arteries are narrowed, they cannot deliver blood properly. This results in various abnormal sensations, including numbness in the big toe. In addition to abnormal sensations, peripheral artery disease may also cause pain, change in leg color, sores on the leg or foot, hair loss on the leg, slow toenail growth and weak pulse in the legs and feet, according to MayoClinic.com. Treatment for peripheral artery disease usually consists of a combination of medications and lifestyle changes.