A hernia occurs when an internal part of the body pushes through a weakness in the muscle or surrounding tissue wall.

A hernia usually develops between your chest and hips. In many cases, it causes no or very few symptoms, although you may notice a swelling or lump in your tummy (abdomen) or groin.

The lump can often be pushed back in or disappears when you lie down. Coughing or straining may make the lump appear.

Types of hernia

Some of the more common types of hernia are described below.

Inguinal hernias

Inguinal hernias occur when fatty tissue or a part of your bowel pokes through into your groin at the top of your inner thigh.

This is the most common type of hernia and it mainly affects men. It’s often associated with ageing and repeated strain on the abdomen.

Femoral hernias

Femoral hernias also occur when fatty tissue or a part of your bowel pokes through into your groin at the top of your inner thigh. They’re much less common than inguinal hernias and tend to affect more women than men.

Like inguinal hernias, femoral hernias are also associated with ageing and repeated strain on the abdomen.

Umbilical hernias

Umbilical hernias occur when fatty tissue or a part of your bowel pokes through your abdomen near your belly button (navel).

This type of hernia can occur in babies if the opening in the abdomen through which the umbilical cord passes doesn’t seal properly after birth. Adults can also be affected, possibly as a result of repeated strain on the abdomen.

Hiatus hernias

Hiatus hernias occur when part of the stomach pushes up into your chest by squeezing through an opening in the diaphragm (the thin sheet of muscle that separates the chest from the abdomen).

This type of hernia may not have any noticeable symptoms, although it can cause heartburn in some people.

It’s not exactly clear what causes hiatus hernias, but it may be the result of the diaphragm becoming weak with age or pressure on the abdomen.

Other types of hernia

Other types of hernia that can affect the abdomen include:

  • incisional hernias – where tissue pokes through a surgical wound in your abdomen that hasn’t fully healed
  • epigastric hernias – where fatty tissue pokes through your abdomen, between your navel and the lower part of your breastbone (sternum)
  • spigelian hernias – where part of your bowel pokes through your abdomen at the side of your abdominal muscle, below your navel
  • diaphragmatic hernias – where organs in your abdomen move into your chest through an opening in the diaphragm; this can also affect babies if their diaphragm doesn’t develop properly in the womb
  • muscle hernias – where part of a muscle pokes through your abdomen; they also occur in leg muscles as the result of a sports injury

You should go the accident and emergency (A&E) department of your nearest hospital immediately if you have a hernia and you develop any of the following symptoms:

  • sudden, severe pain
  • vomiting
  • difficulty passing stools (constipation) or wind
  • the hernia becomes firm or tender, or can’t be pushed back in

These symptoms could mean that either:

  • the blood supply to a section of organ or tissue trapped in the hernia has become cut off (strangulation)
  • a piece of bowel has entered the hernia and become blocked (obstruction)
  • A strangulated hernia and obstructed bowel are medical emergencies and need to be treated as soon as possible.

Assessing a hernia

A number of factors will be considered when deciding whether surgery is appropriate, including:

  • the type of hernia – some types of hernia are more likely to become strangulated, or cause a bowel obstruction, than others
  • the content of your hernia – if the hernia contains a part of your bowel, muscle or other tissue, there may be a risk of strangulation or obstruction
  • your symptoms and the impact on your daily life – surgery may be recommended if your symptoms are severe or getting worse, or if the hernia is affecting your ability to carry out your normal activities
  • your general health – surgery may be too much of a risk if your general health is poor

Although most hernias won’t get better without surgery, they won’t necessarily get worse. In some cases, the risks of surgery outweigh the potential benefits.

Surgery for a hernia

There are two main ways surgery for hernias can be carried out:

open surgery – where one cut is made to allow the surgeon to push the lump back into the abdomen

keyhole (laparoscopic) surgery – this is a less invasive, but more difficult, technique where several smaller cuts are made, allowing the surgeon to use various special instruments to repair the hernia

Most people are able to go home the same day or the day after surgery and make a full recovery within a few weeks.