The largest single nerve in the human body is the sciatic nerve which runs from each side of the lower spine to the buttock and into the back of the thigh to the foot. The sciatic nerve has an important role since it connects the spinal cord to the leg and foot muscles.
Sciatica or lumbar radiculopathy is any type of pain that is felt along the sciatic nerve. Compression in the spinal nerve is one of the common causes of sciatica. Sciatic symptoms felt depend on the degree of compression and which spinal nerve is affected. Sciatic pain is often caused by a herniated disc, which irritates the L5 or S1 nerve root at the lower spine. The nerve roots that form the sciatic nerve are very sensitive. Also, a herniated disc contains proteins that easily inflames and irritates the nerve. An irritated nerve will result in pain in the rear and back of the thigh and calf, and may even reach the foot. Sciatic symptoms include numbness, tingling, burning, and prickling sensations on one or both legs, which may have started from the low back or buttock and moved down to the back thigh. Patients report feeling a sharp kind of pain that is somehow similar to being burned or electrocuted. Numbness, tingling, and prickling are also other observable symptoms. In other cases, leg and foot weakness are also observed. Sciatica symptoms tend to be worse when a person is standing or sitting still and will feel better when the patient is walking or lying down.
Sciatica is not considered a diagnosis, but a symptom. The term sciatica literally means that there is pain caused by compression of the sciatic nerve. Diagnosis will point to the cause of the pain, such as a herniated disc or spinal abnormality.