Sciatica: what kind of disease is it and what does the sciatic nerve have to do with it

First there is a pulling sensation in the lower back — as if someone is slowly tightening a dull string. Then a hot stripe runs down the back of the thigh to the very foot, and stepping on the leg becomes frightening. This is how sciatica manifests — pain associated with the sciatic nerve.

What sciatica is and where the sciatic nerve runs

Sciatica is not a separate disease but a symptom of a problem with the sciatic nerve, the largest nerve in the body. It runs from the lower back down the leg to the feet, controls the muscles of the back of the knee and lower leg, and provides sensation to the back of the thigh, part of the lower leg, and the sole. Sciatica is described as pain in the lumbosacral region that radiates downward along the course of the nerve. Usually one side is affected — left or right.

Why sciatica occurs: main causes

The mechanism is the same: something presses on or rubs the nerve. Beyond that, the variants diverge, and the doctor's approach depends on them.

• herniated intervertebral disc — the soft cushion between vertebrae bulges out; this is the most common cause, and the likelihood is higher with age;
• spinal canal stenosis — the space where the nerves pass narrows;
• spondylolisthesis — one of the vertebrae shifts relative to another;
• back injury, such as a pelvic fracture;
• piriformis syndrome, inflammation of the sciatic nerve, osteochondrosis, lumbar radiculitis.

In some cases the cause cannot be found.

How sciatic nerve neuralgia manifests

Symptoms most often affect the buttock and the back of one leg, often together with the foot and toes. Sensations vary: sharp burning pain down the leg, tingling as if a limb has gone numb from pressure, numbness, weakness. It can start suddenly or develop gradually. Pain worsens with movement, sneezing, and coughing. There may also be pain in the back, but it is usually weaker than in the leg.

How sciatica differs from radiculitis and other back pain

The boundary here lies not so much in the name as in where the pain travels. Radiculitis, osteochondrosis, and piriformis syndrome are conditions that can cause sciatica: the term itself describes the spread of pain along the course of the sciatic nerve, not its root cause. There is also a simple guide: if only the back hurts, it is probably not sciatica. The picture of sciatica is pain down the leg, often with numbness and weakness.

How the cause of sciatica is identified

The doctor asks how the pain began, where it travels, what makes it worse, and examines the leg — checking sensation, muscle strength, and reflexes. To see the structure of the spine, imaging is ordered: MRI or CT of the spine. These examinations help understand what exactly is irritating the nerve — a bulging disc, a narrowed canal, or a displaced vertebra.

Sciatica usually resolves within several weeks or months, but it can last longer and recur. If the pain has not decreased within several weeks, is worsening, or interferes with everyday activities — that is a reason to see a doctor rather than wait for it to resolve on its own.

When to seek urgent medical help

Pain along the course of the nerve by itself is not a reason to call an ambulance. An emergency is signs of a serious back problem that require hospital care.

By itself it is not a reason to call an ambulance; 103 or 112 — if sciatica has appeared on both sides, if weakness or numbness in both legs is severe or increasing, if the perineum or the area around the anus is numb, if it is difficult to start urinating, it is impossible to urinate, or urine is not retained — and this is unusual for you, if you do not feel the urge to defecate or cannot hold stool — and this is also unusual for you.

This material is for reference: it helps to understand what is happening and what to ask the doctor, but does not replace a consultation — the diagnosis and examinations are prescribed by a specialist.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer