Disc herniation

What it means

Each spinal cushion has a tough outer ring and a softer, jelly-like centre. A herniation is what happens when the outer ring weakens or splits in one spot and a bit of the inner jelly squeezes through, forming a small protruding lump on the edge of the cushion. The cushion as a whole stays in place, but that focused pocket can crowd the nerves running close by.

Why it appears on a CT or MRI report

Radiologists describe the level (for example L5-S1 or C6-C7), the side (left, right, or central), the exact location around the cushion (paracentral, foraminal, or far lateral), and whether the lump is touching, displacing, or pinning a nerve root. You may also see "protrusion" for a wide-based lump, "extrusion" for a narrower one that has pushed further out, or "sequestration" if a fragment has separated. These words describe the shape, not the severity of your symptoms.

What it usually means

Most herniations cause arm pain (if in the neck) or leg pain (if in the lower back) that follows the path of the irritated nerve — sciatica is the classic example. The good news is that most herniations get better on their own. Studies that re-scan people months later often show the lump shrinking or even disappearing, and pain settles for the majority within six to twelve weeks with rest, gentle movement, and time. Surgery is reserved for cases that don't improve, get worse, or come with real nerve weakness. Crucially, herniations are also found in scans of people with no pain at all, so the picture has to match the symptoms before treatment decisions are made. Severity on imaging and severity of pain are only loosely related.

When to follow up

Talk to your doctor if you have shooting pain down one arm or leg, numbness or tingling in a specific patch of skin, or a limb that feels weaker — a foot that catches when walking, or a grip that has lost strength. Most cases are managed with physical therapy, anti-inflammatories, and time. Sudden severe weakness, loss of bladder or bowel control, or numbness in the saddle area is a red-flag emergency and needs same-day care.

A plain-language way to picture it

Picture a jelly donut again, but this time someone has pinched one spot on the dough until the wall thinned and a blob of jelly squeezed out the side. The donut hasn't fallen apart — most of it still looks normal — but that one lump of jelly is now sitting where it shouldn't, and if a nerve runs right next to it, the nerve feels the pressure.