Surgery may be useful in those with a herniated disc that is causing significant pain radiating into the leg, significant leg weakness, bladder problems, or loss of bowel control. Discectomy (the partial removal of a disc that is causing leg pain) can provide pain relief sooner than nonsurgical treatments. Discectomy has better outcomes at one year but not at four to ten years. The less invasive microdiscectomy has not been shown to result in a significantly different outcome than regular discectomy with respect to pain. It might however have less risk of infection.

The presence of cauda equina syndrome (in which there is incontinence, weakness and genital numbness) is considered a medical emergency requiring immediate attention and possibly surgical decompression. Regarding the role of surgery for failed medical therapy in people without a significant neurological deficit, a Cochrane review concluded that "limited evidence is now available to support some aspects of surgical practice".

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.

A direct inguinal hernia is less common (~25–30% of inguinal hernias) and usually occurs in men over 40 years of age.

Men have an 8 times higher incidence of inguinal hernia than women.

Disc herniation can occur in any disc in the spine, but the two most common forms are lumbar disc herniation and cervical disc herniation. The former is the most common, causing lower back pain (lumbago) and often leg pain as well, in which case it is commonly referred to as sciatica. Lumbar disc herniation occurs 15 times more often than cervical (neck) disc herniation, and it is one of the most common causes of lower back pain. The cervical discs are affected 8% of the time and the upper-to-mid-back (thoracic) discs only 1–2% of the time.

The following locations have no discs and are therefore exempt from the risk of disc herniation: the upper two cervical intervertebral spaces, the sacrum, and the coccyx. Most disc herniations occur when a person is in their thirties or forties when the nucleus pulposus is still a gelatin-like substance. With age the nucleus pulposus changes ("dries out") and the risk of herniation is greatly reduced. After age 50 or 60, osteoarthritic degeneration (spondylosis) or spinal stenosis are more likely causes of low back pain or leg pain.

- 4.8% males and 2.5% females older than 35 experience sciatica during their lifetime.

- Of all individuals, 60% to 80% experience back pain during their lifetime.

- In 14%, pain lasts more than 2 weeks.

- Generally, males have a slightly higher incidence than females.

About 27% of males and 3% of females develop a groin hernia at some time in their life. In 2013 about 25 million people had a hernia. Inguinal, femoral and abdominal hernias resulted in 32,500 deaths globally in 2013 and 50,500 in 1990.

Most people with mild to moderate symptoms do not get worse. While many improve in the short term after surgery this improvement decreases somewhat with time. A number of factors present before surgery are able to predict the outcome after surgery, with people with depression, cardiovascular disease and scoliosis doing in general worse while those with more severe stenosis beforehand and better overall health doing better.

The natural evolution of disc disease and degeneration leads to stiffening of the intervertebral joint. This leads to osteophyte formation—a bony overgrowth about the joint. This process is called spondylosis, and is part of the normal aging of the spine. This has been seen in studies of normal and diseased spines. Degenerative changes begin to occur without symptoms as early as age 25–30 years. It is not uncommon for people to experience at least one severe case of low back pain by the age of 35 years. This can be expected to improve and become less prevalent as the individual develops osteophyte formation around the discs.

In the US workers' compensation system, once the threshold of two major spinal surgeries is reached, the vast majority of workers will never return to any form of gainful employment. Beyond two spinal surgeries, any more are likely to make the patient worse, not better.

The most common forms are cervical spinal stenosis, which are at the level of the neck, and lumbar spinal stenosis, at the level of the lower back. Thoracic spinal stenosis, at the level of the mid-back, is much less common.

In lumbar stenosis, the spinal nerve roots in the lower back are compressed which can lead to symptoms of sciatica (tingling, weakness, or numbness that radiates from the low back and into the buttocks and legs).

Cervical spinal stenosis can be far more dangerous by compressing the spinal cord. Cervical canal stenosis may lead to myelopathy, a serious conditions causing symptoms including major body weakness and paralysis. Such severe spinal stenosis symptoms are virtually absent in lumbar stenosis, however, as the spinal cord terminates at the top end of the adult lumbar spine, with only nerve roots (cauda equina) continuing further down. Cervical spinal stenosis is a condition involving narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital or traumatic. Treatment frequently is surgical.

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.

Femoral hernias are more common in multiparous females which results from elevated intra-abdominal pressure that dilates the femoral vein and which in turn stretches femoral ring. Such a constant pressure causes preperitoneal fat to insinuate in the femoral ring consequence of which is development of femoral peritoneal sac.

Any of the factors below may cause the spaces in the spine to narrow.

- Spinal ligaments can thicken ("ligamenta flava")

- Bone spurs develop on the bone and into the spinal canal or foraminal openings

- Intervertebral discs may bulge or herniate into the canal or foraminal openings

- Degenerative disc disease causes narrowing of the spaces

- Facet joints break down

- Compression fractures of the spine, which are common in osteoporosis

- Cysts form on the facet joints causing compression of the spinal sac of nerves (thecal sac)

No set risk factors have been clearly defined for CES at this point in time. Individuals most at risk for disc herniation are the most likely to develop CES. Race has little influence with the notable exception that African Americans appear slightly less likely to develop CES than other groups; similarly, men are slightly more likely to develop CES than women. Middle age also appears to be a notable risk factor, as those populations are more likely to develop a herniated disc; heavy lifting can also be inferred as a risk factor for CES.

An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal. Symptoms are present in about 66% of affected people. This may include pain or discomfort especially with coughing, exercise, or bowel movements. Often it gets worse throughout the day and improves when lying down. A bulging area may occur that becomes larger when bearing down. Inguinal hernias occur more often on the right than left side. The main concern is strangulation, where the blood supply to part of the intestine is blocked. This usually produces severe pain and tenderness of the area.

Risk factors for the development of a hernia include: smoking, chronic obstructive pulmonary disease, obesity, pregnancy, peritoneal dialysis, collagen vascular disease, and previous open appendectomy, among others. Hernias are partly genetic and occur more often in certain families. It is unclear if inguinal hernias are associated with heavy lifting. Hernias can often be diagnosed based on signs and symptoms. Occasionally medical imaging is used to confirm the diagnosis or rule out other possible causes.

Groin hernias that do not cause symptoms in males do not need to be repaired. Repair, however, is generally recommended in females due to the higher rate of femoral hernias which have more complications. If strangulation occurs immediate surgery is required. Repair may be done by open surgery or by laparoscopic surgery. Open surgery has the benefit of possibly being done under local anesthesia rather than general anesthesia. Laparoscopic surgery generally has less pain following the procedure.

In 2015 inguinal, femoral and abdominal hernias affected about 18.5 million people. About 27% of males and 3% of females develop a groin hernia at some time in their life. Groin hernias occur most often before the age of one and after the age of fifty. Globally, inguinal, femoral and abdominal hernias resulted in 60,000 deaths in 2015 and 55,000 in 1990.

Scoliosis affects 2–3% of the United States population, which is equivalent to about 5 to 9 million cases. A scoliosis spinal column's curve of 10° or less affects 1.5% to 3% of individuals. The age of onset is usually between 10 years and 15 years (can occur at a younger age) in children and adolescents, making up to 85% of those diagnosed. This is seen to be due to rapid growth spurts occurring at puberty when spinal development is most relenting to genetic and environmental influences. Because female adolescents undergo growth spurts before postural musculoskeletal maturity, scoliosis is more prevalent among females. Although fewer cases are present today using Cobb angle analysis for diagnosis, scoliosis remains a prevailing condition, appearing in otherwise healthy children. Incidence of idiopathic scoliosis (IS) stops after puberty when skeletal maturity is reached, however, further curvature may proceed during late adulthood due to vertebral osteoporosis and weakened musculature.

Cervical spinal stenosis is a bone disease involving the narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital. Treatment is frequently surgical.

Cervical spinal stenosis is one of the most common forms of spinal stenosis, along with lumbar spinal stenosis (which occurs at the level of the lower back instead of in the neck). Thoracic spinal stenosis, at the level of the mid-back, is much less common. Cervical spinal stenosis can be far more dangerous by compressing the spinal cord. Cervical canal stenosis may lead to serious symptoms such as major body weakness and paralysis. Such severe spinal stenosis symptoms are virtually absent in lumbar stenosis, however, as the spinal cord terminates at the top end of the adult lumbar spine, with only nerve roots (cauda equina) continuing further down. Cervical spinal stenosis is a condition involving narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital or traumatic. Treatment frequently is surgical.

An acquired umbilical hernia directly results from increased intra-abdominal pressure caused by obesity, heavy lifting, a long history of coughing, or multiple pregnancies.

There are many causes of scoliosis, including spinal deformities, neuromuscular problems, and inherited diseases or conditions caused by the environment.

An estimated 65% of scoliosis cases are idiopathic, about 15% are congenital and about 10% are secondary to a neuromuscular disease.

Idiopathic scoliosis represents a majority of cases, but its causes are largely unknown. Results of recent studies indicate potential heritability of the disorder. About 38% of variance in scoliosis risk is due to genetic factors, and 62% is due to the environment. The genetics are likely complex however, given the inconsistent inheritance and discordance among monozygotic twins. The specific genes that contribute to development of scoliosis have not been conclusively identified. At least one gene, "CHD7", has been associated with the idiopathic form of scoliosis.

Several candidate gene studies have found associations between idiopathic scoliosis and genes mediating bone formation, bone metabolism, and connective tissue structure. Several genome-wide studies have identified a number of loci as significantly linked to idiopathic scoliosis. In 2006 idiopathic scoliosis was linked with three microsatellite polymorphisms in the MATN1 gene (encoding for "Matrilin 1, cartilage matrix protein"). Fifty-three single nucleotide polymorphism markers in the DNA that are significantly associated with adolescent idiopathic scoliosis were identified through a genome-wide association study.

Adolescent idiopathic scoliosis (AIS) has no clear causal agent, and is generally believed to be multifactorial. The prevalence of scoliosis is 1% to 2% among adolescents, however the likelihood of progression among adolescents with a Cobb angle of less than 20° is about 10% to 20%.

Congenital scoliosis can be attributed to a malformation of the spine during weeks three to six "in utero" due to a failure of formation, a failure of segmentation, or a combination of stimuli. Incomplete and abnormal segmentation results in an abnormally shaped vertebra, at times fused to a normal vertebra or unilaterally fused vertebrae, leading to the abnormal lateral curvature of the spine.

Vertebral anomalies is associated with an increased incidence of some other specific anomalies as well, together being called the VACTERL association:

- V - "Vertebral anomalies"

- A - Anal atresia

- C - Cardiovascular anomalies

- T - Tracheoesophageal fistula

- E - Esophageal atresia

- R - Renal (Kidney) and/or radial anomalies

- L - Limb defects

A hernia is caused by the protrusion of a viscus (in the case of groin hernias, an intraabdominal organ) through a weakness in the containing wall. This weakness may be inherent, as in the case of inguinal, femoral and umbilical hernias. On the other hand, the weakness may be caused by surgical incision through the muscles of the abdominal/thoracic wall. Hernias occurring through these are called incisional hernias.

Femoral hernias occur just below the inguinal ligament, when abdominal contents pass through a naturally occurring weakness called the femoral canal. Femoral hernias are a relatively uncommon type, accounting for only 3% of all hernias. While femoral hernias can occur in both males and females, almost all of them develop in women because of the wider bone structure of the female pelvis. Femoral hernias are more common in adults than in children. Those that do occur in children are more likely to be associated with a connective tissue disorder or with conditions that increase intra-abdominal pressure. Seventy percent of pediatric cases of femoral hernias occur in infants under the age of one.

A reducible femoral hernia occurs when a femoral hernia can be pushed back into the abdomen, either spontaneously or with manipulation, but most likely, spontaneously. This is the most common type of femoral hernia and is usually painless.

An irreducible femoral hernia occurs when a femoral hernia becomes stuck in the femoral canal. This can cause pain and a feeling of illness.

An obstructed femoral hernia occurs when a part of the intestine becomes intertwined with the hernia, causing an intestinal obstruction. The obstruction may grow and the hernia can become increasingly painful. Vomiting may also result.

A strangulated femoral hernia occurs when a femoral hernia blocks blood supply to part of the bowel - the loop of bowel loses its blood supply. Strangulation can happen in all hernias, but is more common in femoral and inguinal hernias due to their narrow "necks". Nausea, vomiting, and severe abdominal pain may occur with a strangulated hernia. This is a medical emergency. A strangulated intestine can result in necrosis (tissue death) followed by gangrene (tissue decay). This is a life-threatening condition requiring immediate surgery.

A femoral hernia may be either reducible or irreducible, and each type can also present as either (or both) obstructed or strangulated.

The term incarcerated femoral hernia is sometimes used, but may have different meanings to different authors and physicians. For example: "Sometimes the hernia can get stuck in the canal and is called an irreducible or incarcerated femoral hernia." "The term 'incarcerated' is sometimes used to describe an [obstructed] hernia that is irreducible but not strangulated. Thus, an irreducible, obstructed hernia can also be called an incarcerated one." "Incarcerated hernia: a hernia that cannot be reduced. May lead to bowel obstruction but is not associated with vascular compromise."

A hernia can be described as reducible if the contents within the sac can be pushed back through the defect into the peritoneal cavity, whereas with an incarcerated hernia, the contents are stuck in the hernia sac.

However, the term "incarcerated" seems to always imply that the femoral hernia is at least irreducible.

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).

Potential non-surgical treatments include:

- Education about the course of the condition and how to relieve symptoms

- Medicines to relieve pain and inflammation, such as acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs)

- Exercise, to maintain or achieve overall good health, aerobic exercise, such as riding a stationary bicycle, which allows for a forward lean, walking, or swimming can relieve symptoms

- Weight loss, to relieve symptoms and slow progression of the stenosis

- Physical therapy, to provide education, instruction, and support for self-care; physical therapy instructs on stretching and strength exercises that may lead to a decrease in pain and other symptoms

CES can be caused by lumbar spinal stenosis, which is when the diameter of the spinal canal narrows. This could be the result of a degenerative process of the spine (such as osteoarthritis) or a developmental defect which is present at birth. In the most severe cases of spondylolisthesis cauda equina syndrome can result.

A significant complication of diaphragmatic rupture is traumatic diaphragmatic herniation: organs such as the stomach that herniate into the chest cavity and may be strangulated, losing their blood supply. Herniation of abdominal organs is present in 3–4% of people with abdominal trauma who present to a trauma center.

Bochdalek hernias make up about 0.17% to 6% of all diaphragmatic hernia cases and about one in every 2200 to 12,500 births every year. Babies who are born with a Bochdalek hernia are more than likely to have another birth defect caused by the hernia. About twenty percent of those children born with a Bochdalek hernia, also have a congenital heart defect. In addition, infants born with this condition may also have other abnormalities. "Between five and sixteen [percent of infants] have a chromosomal abnormality." In most cases, left-sided hernias or Bochdalek hernias have a ratio of 3:2 of males to females. In other words, Bochdalek hernias are more common in men.

Hemivertebrae are wedge-shaped vertebrae and therefore can cause an angle in the spine (such as kyphosis, scoliosis, and lordosis).

Among the congenital vertebral anomalies, hemivertebrae are the most likely to cause neurologic problems. The most common location is the midthoracic vertebrae, especially the eighth (T8). Neurologic signs result from severe angulation of the spine, narrowing of the spinal canal, instability of the spine, and luxation or fracture of the vertebrae. Signs include rear limb weakness or paralysis, urinary or fecal incontinence, and spinal pain. Most cases of hemivertebrae have no or mild symptoms, so treatment is usually conservative. Severe cases may respond to surgical spinal cord decompression and vertebral stabilization.

Associations

Recognised associations are many and include:

Aicardi syndrome,

cleidocranial dysostosis,

gastroschisis 3,

Gorlin syndrome,

fetal pyelectasis 3,

Jarcho-Levin syndrome,

OEIS complex,

VACTERL association.

The probable cause of hemivertebrae is a lack of blood supply causing part of the vertebrae not to form.

Hemivertebrae in dogs are most common in the tail, resulting in a screw shape.

Possible causes that lead to the condition of Lumbar hyperlordosis are the following:

- Spines – Natural factors of how spines are formed greatly increase certain individuals' likelihood to experience a strain or sprain in their back or neck. Factors such as having more lumbar vertebrae allowing for too much flexibility, and then in cases of less lumbar the individual not reaching their necessity for flexibility and then pushing their bodies to injury.

- Legs – Another odd body formation is when an individual has a leg shorter than the other, which can be immediate cause for imbalance of hips then putting strain on the posture of the back which an individual has to adjust into vulnerable positions to meet aesthetic appearances. This can lead to permanent damage in the back. Genu recurvatum (sway back knees) is also a factor that forces a dancer to adjust into unstable postures.

- Hips – Common problems in the hips are tight hip flexors, which causes for poor lifting posture, hip flexion contracture, which means the lack of postural awareness, and thoracic hyperkyphosis, which causes the individual to compensate for limited hip turn out (which is essential to dances such as ballet). Weak psoas (short for iliopsoas-muscle that controls the hip flexor) force the dancer to lift from strength of their back instead of from the hip when lifting their leg into arabesque or attitude. This causes great stress and risk of injury, especially because the dancer will have to compensate to obtain the positions required.

- Muscles – One of the greatest contributors is uneven muscles. Because all muscles have a muscle that works in opposition to it, it is imperative that to keep all muscles protected, the opposite muscle is not stronger than the muscle at risk. In the situation of lumbar lordosis, abdominal muscles are weaker than the muscles in the lumbar spine and the hamstring muscles. The muscular imbalance results in pulling down the pelvis in the front of the body, creating the swayback in the spine.

- Growth spurt – Younger dancers are more at risk for development of lumbar hyperlordosis because the lumbar fascia and hamstrings tighten when a child starts to experience a growth spurt into adolescence.

Technical factors

- Improper lifts – When male dancers are performing dance lifts with another dancer they are extremely prone to lift in the incorrect posture, pushing their arms up to lift the other dancer, while letting their core and spine curve which is easy to then hyperlordosis in a dancer's back.

- Overuse – Over 45% of anatomical sites of injury in dancers are in the lower back. This can be attributed to the strains of repetitive dance training may lead to minor trauma. If the damaged site is not given time to heal the damage of the injury will increase. Abrupt increases in dance intensity or sudden changes in dance choreography do not allow the body to adapt to the new stresses. New styles of dance, returning to dance, or increasing dance time by a great deal will result in exhaustion of the body.