The diagnosis is largely a clinical one, generally done by physical examination of the groin. However, in obese patients, imaging in the form of ultrasonography, CT or MRI may aid in the diagnosis. An abdominal x-ray showing small bowel obstruction in a female patient with a painful groin lump needs no further investigation.

Several other conditions have a similar presentation and must be considered when forming the diagnosis: inguinal hernia, an enlarged inguinal lymph node, aneurysm of the femoral artery, saphena varix, and an abscess of the psoas.

The benefits of the use of an external device to maintain reduction of the hernia without repairing the underlying defect (such as hernia trusses, trunks, belts, etc.) are unclear.

Femoral hernias, like most other hernias, usually need operative intervention. This should ideally be done as an elective (non-emergency) procedure. However, because of the high incidence of complications, femoral hernias often need emergency surgery.

There is currently no medical recommendation about how to manage an inguinal hernia condition in adults, due to the fact that, until recently, elective surgery used to be recommended. The hernia truss is intended to contain a reducible inguinal hernia within the abdomen. It is not considered to provide a cure, and if the pads are hard and intrude into the hernia aperture they may cause scarring and enlargement of the aperture. In addition, most trusses with older designs are not able effectively to contain the hernia at all times, because their pads do not remain permanently in contact with the hernia. The more modern variety of truss is made with non-intrusive flat pads and comes with a guarantee to hold the hernia securely during all activities. Although there is as yet no proof that such devices can prevent an inguinal hernia from progressing, they have been described by users as providing greater confidence and comfort when carrying out physically demanding tasks. A truss also increases the probability of complications, which include strangulation of the hernia, atrophy of the spermatic cord, and atrophy of the fascial margins. This allows the defect to enlarge and makes subsequent repair more difficult. Their popularity is likely to increase, as many individuals with small, painless hernias are now delaying hernia surgery due to the risk of post-herniorrhaphy pain syndrome. The elasticised pants used by athletes also provide useful support for the smaller hernia.

Many people are managed through day surgery centers, and are able to return to work within a week or two, while intense activities are prohibited for a longer period. People who have their hernias repaired with mesh often recover within a month, though pain can last longer. Surgical complications include pain that lasts more than three months, surgical site infections, nerve and blood vessel injuries, injury to nearby organs, and hernia recurrence. Pain that lasts more than three months occurs in about 10% of people following hernia repair.

The diagnosis of a hiatus hernia is typically made through an upper GI series, endoscopy or high resolution manometry.

One way to determine if a baby does in fact have a Bochdalek hernia, would be to have a pediatrician perform a physical on the infant. A chest x-ray can also be done to examine the abnormalities of not only the lungs but also the diaphragm and the intestine. In addition to these, a doctor can also take a blood test, drawing arterial blood to check and determine how well the baby is breathing and his or her ability to breathe. A chromosomal test (done by testing the blood) can also be performed to determine whether or not the problem was genetic. The doctors can also take an ultrasound of the heart (echocardiogram) to evaluate the health of the heart.

Differential diagnosis of the symptoms of inguinal hernia mainly includes the following potential conditions:

- Femoral hernia

- Epididymitis

- Testicular torsion

- Lipomas

- Inguinal adenopathy (Lymph node Swelling)

- Groin abscess

- Saphenous vein dilation, called Saphena varix

- Vascular aneurysm or pseudoaneurysm

- Hydrocele

- Varicocele

- Cryptorchidism (Undescended testes)

In some communities mothers routinely push the small bulge back in and tape a coin over the palpable hernia hole until closure occurs. This practice is not medically recommended as there is a small risk of trapping a loop of bowel under part of the coin resulting in a small area of ischemic bowel. This "fix" does not help and germs may accumulate under the tape, causing infection. The use of bandages or other articles to continuously reduce the hernia is not evidence-based.

An umbilical hernia can be fixed in two different ways. The surgeon can opt to stitch the walls of the abdominal or he/she can place mesh over the opening and stitch it to the abdominal walls. The latter is of a stronger hold and is commonly used for larger defects in the abdominal wall. Most surgeons will not repair the hernia until 5–6 years after the baby is born. Most umbilical hernias in infants and children close spontaneously and rarely have complications of gastrointestinal-content incarcerations.

How far the projection of the swelling extends from the surface of the abdomen (the belly) varies from child to child. In some, it may be just a small protrusion; in others it may be a large rounded swelling that bulges out when the baby cries. It may hardly be visible when the child is quiet and or sleeping.

Normally, the abdominal muscles converge and fuse at the umbilicus during the formation stage, however, in some cases, there remains a gap where the muscles do not close and through this gap the inner intestines come up and bulge under the skin, giving rise to an umbilical hernia. The bulge and its contents can easily be pushed back and reduced into the abdominal cavity.

In contrast to an inguinal hernia, the complication incidence is very low, and in addition, the gap in the muscles usually closes with time and the hernia disappears on its own. The treatment of this condition is essentially conservative: observation allowing the child to grow up and see if it disappears. Operation and closure of the defect is required only if the hernia persists after the age of 3 years or if the child has an episode of complication during the period of observation like irreducibility, intestinal obstruction, abdominal distension with vomiting, or red shiny painful skin over the swelling. Surgery is always done under anesthesia. The defect in the muscles is defined and the edges of the muscles are brought together with sutures to close the defect. In general, the child needs to stay in the hospital for 2 days and the healing is complete within 8 days.

At times, there may be a fleshy red swelling seen in the hollow of the umbilicus that persists after the cord has fallen off. It may bleed on touch, or may stain the clothes that come in contact with it. This needs to be shown to a pediatric surgeon. This is most likely to be an umbilical polyp and the therapy is to tie it at the base with a stitch so that it falls off and there is no bleeding. Alternatively, it may be an umbilical granuloma that responds well to local application of dry salt or silver nitrate but may take a few weeks to heal and dry.

Traditional "open" repair of incisional hernias can be quite difficult and complicated. The weakened tissue of the abdominal wall is re-incised and a repair is reinforced using a prosthetic mesh. Complications, particularly infection of the incision, frequently occur because of the large size of the incision required to perform this surgery. A mesh infection after this type of hernia repair most frequently requires a complete removal of the mesh and ultimately results in surgical failure. In addition, large incisions required for open repair are commonly associated with significant postoperative pain. Reported recurrence rates after open repair are up to 20% and influenced by mesh size and fixation type.

Laparoscopic incisional hernia repair is a new method of surgery for this condition. The operation is performed using surgical microscopes and specialized instruments. The surgical mesh is placed into the abdomen underneath the abdominal muscles through small incisions to the side of the hernia. In this manner, the weakened tissue of the original hernia is never re-incised to perform the repair, and one can minimize the potential for wound complications such as infections. In addition, performance of the operation through smaller incisions can make the operation less painful and speed recovery. Laparoscopic repair has been demonstrated to be safe and a more resilient repair than open incisional hernia repair.

Computed tomography scans of the suspected areas with intravenous contrast can assist in diagnosis.

Symptomatic epigastric hernias are repaired with surgery. Even if they are asymptomatic, they can be surgically corrected for cosmetic reasons. In general, cosmetic surgery on infants is delayed until the infant is older and better able to tolerate anaesthesia.

Four types of esophageal hiatal hernia are identified:

Type I: A type I hernia is also known as a sliding hiatal hernia. There is a widening of the muscular hiatal tunnel and circumferential laxity of the phrenoesophageal membrane, allowing a portion of the gastric cardia to herniate upward into the posterior mediastinum. The clinical significance of type I hernias is in their association with reflux disease. Sliding hernias are the most common type and account for 95% of all hiatal hernias. (C)

Type II: A type II hernia results from a localized defect in the phrenoesophageal membrane while the gastroesophageal junction remains fixed to the pre aortic fascia and the median arcuate ligament. The gastric fundus then serves as the leading point of herniation. Although type II hernias are associated with reflux disease, their primary clinical significance lies in the potential for mechanical complications. (D)

Type III: Type III hernias have elements of both types I and II hernias. With progressive enlargement of the hernia through the hiatus, the phrenoesophageal membrane stretches, displacing the gastroesophageal junction above the diaphragm, thereby adding a sliding element to the type II hernia.

Type IV: Type IV hiatus hernia is associated with a large defect in the phrenoesophageal membrane, allowing other organs, such as colon, spleen, pancreas and small intestine to enter the hernia sac.

The end stage of type I and type II hernias occurs when the whole stomach migrates up into the chest by rotating 180° around its longitudinal axis, with the cardia and pylorus as fixed points. In this situation the abnormality is usually referred to as an intrathoracic stomach.

Bochdalek hernia can be a life-threatening condition. Approximately 85.3% of newborns born with a Bochdalek hernia are immediately high risk. Infants born with a Bochdalek hernia have a "high mortality rate due to respiratory insufficiency". Between 25–60% of infants with a Bochdalek hernia die. The lungs, diaphragm, and digestive system are all forming at the same time, so when a Bochdalek hernia permits the abdominal organs to invade the chest cavity rather than remain under the diaphragm in the correct position, it puts the infant in critical condition. These "foreign bodies" in the chest cavity compress the lungs, impairing their proper development and causing pulmonary hypoplasia. Since the lungs of infants suffering from a Bochdalek hernia have fewer alveoli than normal lungs, Bochdalek hernias are life-threatening conditions due to respiratory distress. Also, if the invasion of the intestine or stomach punctures the lung, then the lungs cannot fill completely with air. The baby will not be healthy or stable with this condition because he or she cannot take in enough air and oxygen to keep the body operating properly. Like the lungs, the intestines may also have trouble developing correctly. If the intestines are trapped within the lungs, then the lungs and intestines may not be receiving the amount of blood they need to stay healthy and function properly.

Navels with the umbilical tip protruding past the umbilical skin ("outies") are often mistaken for umbilical hernias, which are a completely different shape. Treatment for cosmetic purposes is not necessary, unless there are Incarceration refers to the inability to reduce the hernia back into the abdominal cavity. Prolonged incarceration can lead to tissue ischemia (strangulation) and shock when untreated.

Umbilical hernias are rare. With a study involving Africans, 92% of children had protrusions, 49% of adults, and 90% of pregnant women. However, a much smaller amount actually suffered from hernias: only 23% of children, 8% of adults, and 15% of pregnant women.

When the orifice is small (< 1 or 2 cm), 90% close within 3 years (some sources state 85% of all umbilical hernias, regardless of size), and if these hernias are asymptomatic, reducible, and don't enlarge, no surgery is needed (and in other cases it must be considered).

Patients typically present with either an intermittent mass, localized pain, or signs of bowel obstruction. Ultrasonography or a CT scan can establish the diagnosis, although CT scan provides the greatest sensitivity and specificity.

These hernias should be repaired because of the high risk of strangulation; fortunately, surgery is straightforward, with only larger defects requiring a mesh prosthesis. Varied Spigelian hernia mesh repair techniques have been described, although evidence suggests laparoscopy results in less morbidity and shorter hospitalization compared with open procedures. Mesh-free laparoscopic suture repair is feasible and safe. This novel uncomplicated approach to small Spigelian hernias combines the benefits of laparoscopic localization, reduction, and closure without the morbidity and cost associated with foreign material.

Congenital diaphragmatic hernia has a mortality rate of 40–62%, with outcomes being more favorable in the absence of other congenital abnormalities. Individual rates vary greatly dependent upon multiple factors: size of hernia, organs involved, additional birth defects, and/or genetic problems, amount of lung growth, age and size at birth, type of treatments, timing of treatments, complications (such as infections) and lack of lung function.

This condition can often be diagnosed before birth and fetal intervention can sometimes help, depending on the severity of the condition.

Infants born with diaphragmatic hernia experience respiratory failure due to both pulmonary hypertension and pulmonary hypoplasia. The first condition is a restriction of blood flow through the lungs thought to be caused by defects in the lung. Pulmonary hypoplasia or decreased lung volume is directly related to the abdominal organs presence in the chest cavity which causes the lungs to be severely undersized, especially on the side of the hernia.

Survival rates for infants with this condition vary, but have generally been increasing through advances in neonatal medicine. Work has been done to correlate survival rates to ultrasound measurements of the lung volume as compared to the baby's head circumference. This figure known as the lung to head ratio (LHR). Still, LHR remains an inconsistent measure of survival. Outcomes of CDH are largely dependent on the severity of the defect and the appropriate timing of treatment.

A small percentage of cases go unrecognized into adulthood.

A diagnosis of pentalogy of Cantrell can often be made before birth (prenatally) sometimes using a fetal ultrasound. An ultrasound is an exam that uses high-frequency sound waves to produce an image of the developing fetus. A fetal ultrasound can detect some of the defects associated with pentalogy of Cantrell. An echocardiography is usually performed to evaluate the extent of the involvement of the heart. An echocardiography is an exam that uses sound waves to produce images of the heart

Magnetic resonance imaging (MRI) may also be performed to assess the degree of certain anomalies such as abdominal wall and pericardial defects. An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues.

In dogs, perineal hernia usually is found on the right side. Most cases are in older intact (not neutered) male dogs (93 percent in one study). Breeds that may be at risk include Welsh Corgis, Boxers, Australian Kelpies, Boston Terriers, Collies, Dachshunds, Old English Sheepdogs, and Pekingese. Perineal hernias are rare in female dogs and uncommon in cats.

Dogs with benign prostatic hyperplasia have been found to have increased relaxin levels and suspected subsequent weakening of the pelvic diaphragm. In cats, perineal hernias are seen most commonly following perineal urethrostomy surgery or secondary to megacolon. Medical treatment consists of treatment of the underlying disease, enemas, and stool softeners. Because only about 20 percent of cases treated medically are free of symptoms, surgery is often necessary. Recurrence is common with or without surgery.

Several surgeries have been described for perineal hernias in dogs. The current standard involves transposition of the internal obturator muscle. This technique has a lower recurrence and complication rate than traditional hernia repair. A new technique uses porcine small intestinal submucosa as a biomaterial to help repair the defect. This is can also be done in combination with internal obturator muscle transposition, especially when that muscle is weak.

Clinically, incisional hernias present as a bulge or protrusion at or near the area of a surgical incision. Virtually any prior abdominal operation can develop an incisional hernia at the scar area (provided adequate healing does not occur due to infection), including large abdominal procedures such as intestinal or vascular surgery, and small incisions, such as (appendix removal or abdominal exploratory surgery). While incisional hernias can occur at any incision, they tend to occur more commonly along a straight line from the xiphoid process of the sternum straight down to the pubis, and are more complex in these regions. Hernias in these areas have a high rate of recurrence if repaired via a simple suture technique under tension. For this reason, it is especially advised that these be repaired via a tension free repair method using a synthetic mesh.

A technetium-99m (99mTc) pertechnetate scan, also called Meckel scan, is the investigation of choice to diagnose Meckel's diverticula in children. This scan detects gastric mucosa; since approximately 50% of symptomatic Meckel's diverticula have ectopic gastric or pancreatic cells contained within them, this is displayed as a spot on the scan distant from the stomach itself. In children, this scan is highly accurate and noninvasive, with 95% specificity and 85% sensitivity; however, in adults the test is only 9% specific and 62% sensitive.

Patients with these misplaced gastric cells may experience peptic ulcers as a consequence. Therefore, other tests such as colonoscopy and screenings for bleeding disorders should be performed, and angiography can assist in determining the location and severity of bleeding. Colonoscopy might be helpful to rule out other sources of bleeding but it is not used as an identification tool. Angiography might identify brisk bleeding in patients with Meckel's diverticulum.

Ultrasonography could demonstrate omphaloenteric duct remnants or cysts. Computed tomography (CT scan) might be a useful tool to demonstrate a blind ended and inflamed structure in the mid-abdominal cavity, which is not an appendix.

In asymptomatic patients, Meckel's diverticulum is often diagnosed as an incidental finding during laparoscopy or laparotomy.

Petit's hernia is a hernia that protrudes through the lumbar triangle. This triangle lies in the posterolateral abdominal wall and is bounded anteriorly by the free margin of external oblique muscle, posteriorly by the latissimus dorsi and inferiorly by the iliac crest. The neck (the spot where the hernia protrudes into the opening) is large, and therefore this hernia has a lower risk of strangulating than some other hernias.

Petit's hernia occurs more often in males than in females and more often on the left side than on the right.

The protrusion is put back within the abdomen in the correct position. Stitches are used to strengthen the weakness where the hernia has broken through.

The operation is usually performed under a general anaesthetic.

In most cases this is done as a day case without the need for an overnight stay.