Sciatica, what is it? and why does it hurt?

General description
The term "sciatica" refers to pain that radiates along the path of the sciatic nerve, which branches from the lower back through the hips and buttocks and down each leg. Sciatica usually affects only one side of the body.
Sciatica occurs most often when a herniated disc, a bone spur in the spine, or a narrowing of the spine (spinal canal stenosis) compresses part of the nerve. This causes swelling, pain, and often some numbness in the affected leg.
Although the pain associated with sciatica can be severe, most cases resolve with non-surgical treatments within a few weeks. People with severe sciatica associated with significant leg weakness or changes in the intestine or bladder may be candidates for surgery.

Symptoms
Pain that extends from the lower spine (lumbar) to the buttocks and down the back of the leg is the hallmark of sciatica. You could feel the discomfort almost anywhere along the nerve path, but it is especially likely that it runs down the lower back to the buttocks and the back of the thighs and calf.
The pain can vary widely, from mild pain to a sharp, burning or excruciating pain. Sometimes it can feel like a shock or an electric shock. It can be worse when coughing or sneezing, and sitting for long periods can aggravate symptoms. It usually affects only one side of the body.
Some people also have numbness, tingling, or muscle weakness in the affected leg or foot. You may feel pain in one part of the leg and numbness in another part.

When to see the doctor
Mild sciatica usually goes away over time. Call your doctor if self-care measures fail to alleviate symptoms or if pain lasts for more than a week, is severe, or progressively worsens. Get medical attention right away if:

You experience sudden, severe pain in the lower back or leg and numbness or muscle weakness in the leg
Pain is a consequence of a violent injury, such as a car accident
You have trouble controlling the intestines or bladder
Causes
Sciatica occurs from pinching of the sciatic nerve, usually caused by a herniated disc in the spine or by excessive bone growth (bone spur) in the vertebrae. Much less often, a tumor can cause nerve impingement, or a disease, such as diabetes, can damage the nerve.

Risk factor's
The risk factors for sciatica are as follows:

Age. Age-related changes in the spine, such as herniated discs and bone spurs, are the most common causes of sciatica.
Obesity. By increasing the strain on the spine, excess body weight can contribute to the spinal changes that trigger sciatica.
Profession. A job that requires you to turn your back, carry heavy loads, or drive a car for long periods could be related to the development of sciatica, but there is no conclusive evidence of this relationship.
Remain seated for a long time. People who sit for a long time or have a sedentary lifestyle are more likely to have sciatica than active people.
Diabetes. This disease, which affects the way the body uses blood sugar, increases the risk of nerve damage

Complications
Although most people recover fully from sciatica, usually without treatment, this condition can lead to permanent nerve damage. Seek immediate medical attention if you have the following:

Loss of sensation in the affected leg
Weakness in the affected leg
Impaired bowel or bladder function
Prevention
It is not always possible to prevent sciatica, and this condition may reoccur. Taking the following measures can have a fundamental role in back protection:

Exercise regularly. To keep your back strong, pay special attention to the core muscles, that is, the muscles of the abdomen and the lower back that are essential for good posture and correct alignment. Ask your doctor to recommend specific activities.
Maintain proper posture when sitting. Choose a seat with good lumbar support, armrests and a swivel base. Consider placing a pillow or rolled towel on your lower back to maintain your normal curve. Keep your knees and hips aligned.
Use proper body mechanics. If you are standing for long periods of time, place one foot on a stool or in a small box from time to time. When you lift heavy objects, let your legs do the effort. Go up and down with your back straight. Keep your back straight and bend only your knees. Keep the load close to the body. Avoid lifting the load and turning the body at the same time. Seek help lifting the object if it is heavy or difficult to move.