Herniated disc

3 things to know first

1. A herniated disc is not always painful. Many people have disc changes on MRI without any symptoms.
2. Symptoms depend on whether a nerve is irritated. Pain, numbness, or weakness in an arm or leg can occur when the disc presses on a nerve.
3. Most people improve without surgery. Conservative treatments such as time, physical therapy, and medication help the majority of cases.

What it is

The spine is made up of bones (vertebrae) with cushion-like discs between them. Each disc has a tough outer ring and a softer inner core. A herniated disc occurs when the inner material pushes through a tear or weakness in the outer ring and bulges outward.

If the bulging material presses on or irritates a nearby nerve, it can cause pain, tingling, numbness, or weakness along the path of that nerve. This is often called sciatica when it affects the leg.

Why it appears on your report

Herniated discs are one of the most common findings on MRI of the spine. The radiologist describes where the disc is located, how much it is bulging, and whether it appears to be pressing on nerves or the spinal cord.

How serious is it

Most herniated discs are not serious and improve over time. The level of concern depends on:

• Size and location of the herniation. A small bulge may cause no symptoms, while a larger one pressing on a nerve can be very painful.
• Which nerves are affected. Pressure on certain nerves can cause weakness or numbness in specific areas.
• Whether there is spinal cord involvement. Herniations in the neck or upper back that compress the spinal cord are less common but more serious.

Your doctor will match the MRI findings with your physical exam to decide how significant the herniation is for you.

When to seek care urgently

Seek emergency care if you have:

• Severe or worsening weakness in an arm or leg
• Numbness in the groin or inner thighs (saddle anesthesia)
• Loss of bladder or bowel control
• Severe back pain with fever
• Rapidly worsening symptoms after an injury

These can be signs of cauda equina syndrome, infection, or another serious condition that needs immediate treatment.

What usually happens next

1. Clinical examination. Your doctor will test strength, sensation, and reflexes to see which nerve may be affected.
2. Initial conservative treatment. This usually includes activity modification, pain relief medication, and possibly physical therapy.
3. Consider injections. If pain is severe or persistent, an epidural steroid injection may help reduce nerve inflammation.
4. Evaluate for surgery. Surgery is usually reserved for cases with severe nerve compression, significant weakness, or symptoms that do not improve after several weeks to months of conservative care.

A simple analogy

Imagine a jelly donut. If you press it too hard, the jelly can squeeze out through a crack in the dough. A herniated disc is similar: the soft inner material pushes through a tear in the tougher outer layer. If the "jelly" touches a nearby nerve, it can cause pain or tingling.

Further reading

• NHS — Slipped disc
• Mayo Clinic — Herniated disk