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

Your muscles are usually strong and tight enough to keep your intestines and organs in place, but a hernia can develop if there are any weak spots.

An inguinal (pronounced "ingwinal") hernia is the most common type of hernia.

It can appear as a swelling or lump in your groin, or as an enlarged scrotum (the pouch containing the testicles). The swelling may be painful.

The lump often appears when you're lifting something and disappears when you lie down.

For information on other types of hernia, see:

• femoral hernia
• hiatus hernia
• umbilical hernia

An inguinal hernia usually happens when fatty tissue or a part of your bowel, such as the intestine, pokes through into your groin at the top of your inner thigh.

It pushes through a weak spot in the surrounding muscle wall (the abdominal wall) into an area called the inguinal canal.

Inguinal hernias mainly affect men. Most are thought to be caused by ageing, although they can happen at any age.

This is because as you get older, the muscles surrounding your abdomen (tummy) can become weaker.

Inguinal hernias can sometimes appear suddenly after putting pressure on the abdomen, such as straining on the toilet if you have constipation or carrying and pushing heavy loads.

They have also been linked to having a persistent, heavy cough.

Inguinal hernias can be repaired using surgery to push the bulge back into place and strengthen the weakness in the abdominal wall.

The operation is usually recommended if you have a hernia that causes pain, severe or persistent symptoms, or if any serious complications develop.

Complications that can happen as a result of an inguinal hernia include:

• obstruction – where a section of the bowel becomes stuck in the inguinal canal, causing nausea, vomiting and stomach pain, as well as a painful lump in the groin
• strangulation – where a section of bowel becomes trapped and its blood supply is cut off; this requires emergency surgery within hours to release the trapped tissue and restore its blood supply so it does not die

Surgery gets rid of the hernia to prevent any serious complications, but there's a chance it could return after the operation.

There are 2 ways an inguinal hernia repair can be performed:

• open surgery – where a cut is made to allow the surgeon to push the lump back into the abdomen
• laparoscopic (keyhole) surgery – a less invasive, but more difficult, technique where several smaller cuts are made, allowing the surgeon to use instruments to repair the hernia

There are advantages and disadvantages to both methods. The type of surgery you have depends on which method suits you, and your surgeon's experience.

You should be able to go home the same day or the day after surgery. It's important to follow the instructions you're given while in hospital about how to look after yourself.

This includes eating a good diet to avoid constipation, caring for the wound, and avoiding strenuous activities.

Most people make a full recovery from inguinal hernia repair within 6 weeks, with many being able to return to work and light activities within 2 weeks.

Ask your surgeon or GP for advice on when it's safe for you to drive again. You should also speak to your insurer before driving again after having surgery.

Read more about:

• how an inguinal hernia repair is performed
• recovering from an inguinal hernia repair

An inguinal hernia repair is a routine operation with very few risks. But a small number of hernias can come back at some point after surgery.

Other potential complications of an inguinal hernia repair include:

• blood or fluid building up in the space left by the hernia (this usually gets better without treatment)
• painful swelling and bruising of the testicles or the base of the penis
• pain and numbness in the groin area caused by a nerve being damaged or trapped during surgery
• damage to the blood supply to the testicles
• damage to the vas deferens (the tube that carries sperm to the testicles)

Complications are more likely if you're aged over 50, smoke or have another illness, such as heart disease or breathing problems.