Dog: Hernia

General information

Other common/scientific names: umbilical hernia, inguinal hernia, diaphragmatic hernia, perineal hernia, hiatal hernia, rupture

A hernia is defined as a protrusion of an organ or body part through the tissue in which it is normally contained. This protrusion is referred to as a hernial sac and the organ or body tissue is referred to as the hernial contents. The most common types of hernia seen in dogs are:

Umbilical Hernia

The umbilicus (belly button) is a normal opening in an unborn pup where the blood vessels pass through from the mother to the fetus. This should close at birth. A hernia results when this opening fails to close. Depending on the size of the opening, abdominal fat can protrude through the hole. If the defect is large, intestinal loops can drop into the hernia sac. These hernias are congenital (present at birth).

Cause: Umbilical hernias are thought to be inherited.

Abb. GT2LIIM9: Umbilical hernia.

Abb. GG3UQDO7: Umbilical hernia.
This is a radiograph of a dog with a large umbilical hernia. The arrows are pointing to the hernial sac which contains loops of intestine.

Inguinal Hernia

An inguinal hernia occurs when abdominal contents protrude through the inguinal ring which is located at the inner fold of the rear leg or groin area. If the opening is large enough, an intestinal loop, the urinary bladder or the uterus can become trapped in the sac.

Cause: Inguinal hernias can be congenital or acquired. Both types may have a genetic predisposition. Obesity, trauma and pregnancy are also risk factors for development. Females are more prone to inguinal hernias than males.

Diaphragmatic Hernia

The diaphragm separates the heart and lungs (thorax) from the abdomen. A defect or tear in the diaphragm causes the abdominal organs to enter the thorax. The contents of the hernia will vary with the size of the defect and may include the stomach, liver and intestines.

Cause: Diaphragmatic hernias can be either congenital or traumatic. Traumatic diaphragmatic hernias are caused by a severe blow to the chest or abdomen such as being hit by a car, falling from a height or being kicked.

Abb. GG3UTJAE: Diaphragmatic hernia.
A. This is a radiograph of a congenital diaphragmatic hernia. There is no separation between the chest and abdomen. Intestinal loops (B) can be seen in the pericardium (A). B. This is a radiograph of the same patient after surgery. The chest and abdomen are now separated.

Perineal Hernia

A perineal hernia is a condition in which abdominal contents protrude into the perineal region which is adjacent to the anus. These hernias may involve one or both sides. The hernial sac may contain abdominal fat, small intestine, colon, prostate or urinary bladder.

Cause: The exact cause of a perineal hernia is not understood. A genetic component is thought to be involved. Because non-castrated males are more prone to these hernias, perineal and pelvic muscle weakening due hormones may be a cause. Any condition that causes straining can lead to a perineal hernia.

Hiatal Hernia

The esophagus which carries food from the mouth to the stomach passes through the diaphragm via an opening called the diaphragmatic hiatus as it enters the abdomen. A hiatal hernia is the protrusion of the esophagus and/or part of the stomach through this hiatus into the thorax.

Cause: Hiatal hernias can be either congenital or acquired. Acquired hiatal hernias are caused by chronic vomiting or underlying pulmonary disease.

Cardinal symptom



Clinical signs of a hernia will depend on the type and severity of the hernia. External hernias (umbilical, perineal, inguinal) are characterized by a soft swelling. These hernias can vary depending on the size of the defect. An umbilical hernia is seen as a soft bulge at the umbilicus. A perineal hernia is seen as a soft bulge near the anus while an inguinal hernia is a soft bulge in the groin area. The contents of these hernias may be reduced (pushed back) into the abdomen or they may not be moveable. Most umbilical hernias cause no other signs and may go unnoticed by the owner. However, with a large umbilical, perineal or inguinal hernia, loops of intestine may become twisted and trapped in the sac causing pain, vomiting and anorexia. This condition is an emergency and prompt veterinary attention is needed. Internal hernias (diaphragmatic and hiatal) are not visible externally. With a diaphragmatic hernia, abdominal organs in the chest cause difficulty breathing, abdominal pain, vomiting, cardiac abnormalities and depression. Hiatal hernias cause regurgitation, vomiting, hypersalivation, breathing difficulty and aspiration pneumonia.


Diagnosis of an umbilical, perineal or inguinal hernia can be made from a physical examination. Abdominal ultrasound can help determine if intestinal loops are present in the hernial sac. A digital rectal examination will diagnose a perineal hernia. A diaphragmatic hernia is diagnosed with radiographs of the chest and abdomen. An abdominal ultrasound can also be used. Hiatal hernias can be more difficult to diagnose. Radiographs of the thorax and abdomen are taken. Barium is often given to add contrast and serial radiographs are taken to observe its passage through the intestines. Many times, the barium will highlight the hernia. Endoscopy (using a flexible tube with a lighted scope) can be used to visualize the esophagus and stomach to diagnose a hiatal hernia.


Most hernias are treated by surgical repair where the hernial sac is opened, the contents are replaced (usually to the abdomen) and the sac is sutured closed.

Umbilical hernias can be surgically repaired when the puppy is spayed or castrated. Small hernias may not require surgery.

Inguinal hernias should be surgically repaired at the time of diagnosis.

Perianal hernias should be surgically repaired. Potential postoperative complications include infection, recurrence and fecal incontinence. Older dogs unable to undergo surgery can be managed conservatively with stool softener and enemas.

Diaphragmatic hernias that are not causing respiratory or cardiac issues may not need surgery. However, most of these hernias are due to trauma and surgical correction is necessary.

Hiatal hernias that are acquired can be managed with antacids, antiemetics and medication to strengthen the esophagus muscle. Congenital hernias often require surgical correction.


The prognosis is good for most hernias. Traumatic diaphragmatic hernias caused by an automobile accident are often seen with other life-threatening injuries. Hiatal hernias can result in aspiration pneumonia that can be difficult to treat.


Because of the hereditary predisposition, dogs with hernias (unless caused by trauma or acquired due to an underlying cause) should not be used for breeding.


If your dog has an external hernia that is red and painful to touch, call your veterinarian immediately. Intestinal loops may be entrapped which can result in tissue death and septicemia.

Update version: 4/24/2014, © Copyright by
Join the discussion!
12/2/2012: BES
If your dog has been dignosed with a inguinal hernia please have it corrected right then I wish I had.My dog started coughing 2 years ago I had her checked for heart worms since it was a honking cough it came back negative at this time she was dignoised with a inguinal hernia vet didnt want to do surgery because of the cough and her age he dignoised her with lung cancer.2 years later her saging area turned real hard vet thought bladder had slipped thru did surgery about 12 hours later it was intestient instead of bladder the intestient was dead it was too much to cut off.My dog is at home now shes hanging in but gangreen will probely set it and take her life so please insist on the surgery I wish I had.The cough was from the hernia she didnt have lung cancer.

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