There are several kinds of kyphosis (ICD-10 codes are provided):

- Postural kyphosis (M40.0), the most common type, normally attributed to slouching, can occur in both the old and the young. In the young, it can be called "slouching" and is reversible by correcting muscular imbalances. In the old, it may be a case of hyperkyphosis and called "dowager's hump". About one third of the most severe hyperkyphosis cases in older people have vertebral fractures. Otherwise, the aging body does tend towards a loss of musculoskeletal integrity, and hyperkyphosis can develop due to aging alone.

- Scheuermann's kyphosis (M42.0) is significantly worse cosmetically and can cause varying degrees of pain, and can also affect different areas of the spine (the most common being the midthoracic area). Scheuermann's kyphosis is considered a form of juvenile osteochondrosis of the spine, and is more commonly called Scheuermann's disease. It is found mostly in teenagers and presents a significantly worse deformity than postural kyphosis. A patient suffering from Scheuermann’s kyphosis cannot consciously correct posture. The apex of the curve, located in the thoracic vertebrae, is quite rigid. The patient may feel pain at this apex, which can be aggravated by physical activity and by long periods of standing or sitting. This can have a significantly detrimental effect on their lives, as their level of activity is curbed by their condition; they may feel isolated or uneasy amongst peers if they are children, depending on the level of deformity. Whereas in postural kyphosis, the vertebrae and discs appear normal, in Scheuermann’s kyphosis, they are irregular, often herniated, and wedge-shaped over at least three adjacent levels. Fatigue is a very common symptom, most likely because of the intense muscle work that has to be put into standing or sitting properly. The condition appears to run in families. Most patients who undergo surgery to correct their kyphosis have Scheuermann's disease.

- Congenital kyphosis (Q76.4) can result in infants whose spinal column has not developed correctly in the womb. Vertebrae may be malformed or fused together and can cause further progressive kyphosis as the child develops. Surgical treatment may be necessary at a very early stage and can help maintain a normal curve in coordination with consistent follow-ups to monitor changes. However, the decision to carry out the procedure can be very difficult due to the potential risks to the child. A congenital kyphosis can also suddenly appear in teenage years, more commonly in children with cerebral palsy and other neurological disorders.

- Nutritional kyphosis can result from nutritional deficiencies, especially during childhood, such as vitamin D deficiency (producing rickets), which softens bones and results in curving of the spine and limbs under the child's body weight.

- Gibbus deformity is a form of structural kyphosis, often a "sequela" to tuberculosis.

- Post-traumatic kyphosis (M84.0) can arise from untreated or ineffectively treated vertebral fractures.

Lumbar hyperlordosis is a condition that occurs when the lumbar region (lower back) experiences stress or extra weight and is arched to point of muscle pain or spasms. Lumbar hyperlordosis is a common postural position where the natural curve of the lumbar region of the back is slightly or dramatically accentuated. Commonly known as swayback, it is common in dancers. Imbalances in muscle strength and length are also a cause, such as weak hamstrings, or tight hip flexors (psoas). A major feature of lumbar hyperlordosis is a forward pelvic tilt, resulting in the pelvis resting on top of the thighs.

Other health conditions and disorders can cause hyperlordosis. Achondroplasia (a disorder where bones grow abnormally which can result in short stature as in dwarfism), Spondylolisthesis (a condition in which vertebrae slip forward) and osteoporosis (the most common bone disease in which bone density is lost resulting in bone weakness and increased likelihood of fracture) are some of the most common causes of hyperlordosis. Other causes include obesity, hyperkyphosis (spine curvature disorder in which the thoracic curvature is abnormally rounded), discitits (an inflammation of the intervertebral disc space caused by infection) and benign juvenile lordosis. Other factors may also include those with rare diseases, as is the case with Ehlers Danlos Syndrome (EDS), where hyper-extensive and usually unstable joints (e.g. joints that are problematically much more flexible, frequently to the point of partial or full dislocation) are quite common throughout the body. With such hyper-extensibility, it is also quite common (if not the norm) to find the muscles surrounding the joints to be a major source of compensation when such instability exists.

Excessive lordotic curvature – lumbar hyperlordosis, is also called hollow back, and saddle back (after a similar condition that affects some horses); swayback usually refers to a nearly opposite postural misalignment that can initially look quite similar. Common causes of lumbar hyperlordosis include tight low back muscles, excessive visceral fat, and pregnancy. Rickets, a vitamin D deficiency in children, can cause lumbar lordosis.

Although hyperlordosis gives an impression of a stronger back, incongruently it can lead to moderate to severe lower back pain. The most problematic symptom is that of herniated disc where the dancer has put so much strain on their back that the discs between the vertebrae have been damaged or have ruptured. Technical problems with dancing such as difficulty in the positions of attitude and arabesque can be a sign of weak iliopsoas. Tightness of the iliopsoas results in a dancer having difficulty lifting their leg into high positions. Abdominal muscles being weak and the rectus femoris of the quadriceps being tight are signs that improper muscles are being worked while dancing which leads to lumbar hyperlordosis. The most obvious signs of lumbar hyperlordosis is lower back pain in dancing and pedestrian activities as well as having the appearance of a swayed back.

Kyphosis (from Greek κυφός "kyphos", a hump) is an abnormally excessive convex "kyphotic" curvature of the spine as it occurs in the cervical, thoracic and sacral regions. (Abnormal inward concave "lordotic" curving of the cervical and lumbar regions of the spine is called lordosis.) Kyphosis can be called roundback or Kelso's hunchback. It can result from degenerative diseases such as arthritis; developmental problems, most commonly Scheuermann's disease; osteoporosis with compression fractures of the vertebra; multiple myeloma or trauma. A normal thoracic spine extends from the 1st to the 12th vertebra and should have a slight kyphotic angle, ranging from 20° to 45°. When the "roundness" of the upper spine increases past 45° it is called kyphosis or "hyperkyphosis". Scheuermann's kyphosis is the most classic form of hyperkyphosis and is the result of wedged vertebrae that develop during adolescence. The cause is not currently known and the condition appears to be multifactorial and is seen more frequently in males than females.

In the sense of a deformity, it is the pathological curving of the spine, where parts of the spinal column lose some or all of their lordotic profile. This causes a bowing of the back, seen as a slouching posture.

While most cases of kyphosis are mild and only require routine monitoring, serious cases can be debilitating. High degrees of kyphosis can cause severe pain and discomfort, breathing and digestion difficulties, cardiovascular irregularities, neurological compromise and, in the more severe cases, significantly shortened life spans. These types of high-end curves typically do not respond well to conservative treatment and almost always warrant spinal fusion surgery, which can restore the body's natural degree of curvature.

Symptoms associated with scoliosis can include:

- Pain in back, shoulders, and neck and buttock pain nearest bottom of the back

- Respiratory and/or cardiac problems in severe cases

- Constipation due to curvature causing "tightening" of stomach, intestines, etc.

- Limited mobility secondary to pain or functional limitation in adults

- Painful menstruation

The signs of scoliosis can include:

- Uneven musculature on one side of the spine

- Rib prominence or a prominent shoulder blade, caused by rotation of the rib cage in thoracic scoliosis

- Uneven hips, arms or leg lengths

- Slow nerve action

- Heart and lung problems in severe cases

- Calcium deposits in the cartilage endplate and sometimes in the disc itself

Scheuermann's disease is considered to be a form of juvenile osteochondrosis of the spine. It is found mostly in teenagers and presents a significantly worse deformity than postural kyphosis. Patients suffering with Scheuermann’s kyphosis cannot consciously correct their posture. The apex of their curve, located in the thoracic vertebrae, is quite rigid.

Scheuermann's disease is notorious for causing lower and mid-level back and neck pain, which can be severe and disabling. The sufferer may feel pain at the apex of the curve, which is aggravated by physical activity and by periods of standing or sitting; this can have a significantly detrimental effect to their lives as their level of activity is curbed by their disability. The sufferer may feel isolated or uneasy amongst their peers if they are children, depending on the level of deformity.

In addition to the pain associated with Scheuermann's disease, many sufferers of the disorder have loss of vertebral height, and depending on where the apex of the curve is, may have a visual 'hunchback' or 'roundback'. It has been reported that curves in the lower thoracic region cause more pain, whereas curves in the upper region present a more visual deformity. Nevertheless, it is typically pain or cosmetic reasons that prompt sufferers to seek help for their condition. In studies, kyphosis is better characterized for the thoracic spine than for the lumbar spine.

The seventh and tenth thoracic vertebrae are most commonly affected. It causes backache and spinal curvature. In very serious cases it may cause internal problems and spinal cord damage, but these cases are extremely rare. The curvature of the back decreases height, thus putting pressure on internal organs, wearing them out more quickly than the natural aging process; surgical procedures are almost always recommended in this case.

The following are clear signs of Kyphoscoliosis:

- Abnormal hunch along with a presence of S or C-like shape.

- Uneven lengths of arms and legs

- Presence of associated disorders likes hypertension, neurological disorders

- Abnormal gait

People who have reached skeletal maturity are less likely to have a worsening case. Some severe cases of scoliosis can lead to diminishing lung capacity, pressure exerted on the heart, and restricted physical activities.

Recent longitudinal studies reveal that the most common form of the condition, "late-onset idiopathic scoliosis", causes little physical impairment other than back pain and cosmetic concerns, even when untreated, with mortality rates similar to the general population. Older beliefs that untreated idiopathic scoliosis necessarily progresses into severe (cardiopulmonary) disability by old age have been refuted by later studies.

Kyphosis by itself refers to an excessive convex curvature of spine occurring in the thoracic and sacral regions. A normal thoracic curvature from the 1st to the 12th spine has a naturally occurring convex shape with angles ranging from 20 degrees to 45 degrees. When the curvature goes past 45 degrees, the condition is termed as Kyphosis.

Kyphosis, depending on the extent of curvature can result in many discomforts including breathing and digestion difficulties, cardiovascular issues, and even neurological deformities. The greater the extent of deformity, the more pressing the need becomes for a surgery.

Kyphosis by itself is of several types, including postural kyphosis caused by slouching. Such forms of kyphosis can be reversed to a certain extent by correcting muscular imbalances. The more debilitating version of kyphosis is Scheuermann’s kyphosis, found mostly in teenagers. There are few other causes of Kyphosis as well, such as congenital, nutritional or osteoporosis induced and post-traumatic.

Depending on the type of Kyphosis, the extent of curvature, the age of the patient, various treatment modalities can be suggested including the provision for posture correction, braces, physiotherapy for correcting the muscular imbalance, and finally the surgery. Surgery can be most useful in patients who have an extensive deformity. The rate of post-surgery complications may be higher in elderly patients.

Gibbus deformity is a form of structural kyphosis typically found in the upper lumbar and lower thoracic vertebrae, where one or more adjacent vertebrae become wedged. Gibbus deformity most often develops in young children as a result of spinal tuberculosis and is the result of collapse of vertebral bodies. This can in turn lead to spinal cord compression causing paraplegia.

In addition to tuberculosis, other possible causes of gibbus deformity include pathological diseases, hereditary and congenital conditions, and physical trauma to the spine that results in injury. Gibbus deformity may result from the sail vertebrae associated with cretinism (the childhood form of hypothyroidism), mucopolysaccharidosis (MPS), and certain congenital syndromes, including achondroplasia. Because most children with MPS I (Hurler Syndrome) also exhibit symptoms of a gibbus deformity, the latter can possibly be used to identify the former.

Gibbus deformity is included in a subset of structural kyphosis that is distinguished by a higher-degree angle in the spinal curve that is specific to these forms of kyphosis. Other conditions within this subset include Pott’s disease and Scheuermann kyphosis, but gibbus deformity is marked by an especially sharp angle. Viewed from behind, the resulting hunchback is more easily seen when bending forward. A kyphosis of >70° can be an indication of the need for surgery and these surgeries can be necessary for children as young as two years old, with a reported average of 8 years of age.

Many with Scheuermann's disease often have an excessive lordotic curve in the lumbar spine; this is the body's natural way to compensate for the kyphotic curve above. Interestingly, many with Scheuermann's disease have very large lung capacities and males often have broad, barrel chests. Most people have forced vital capacity (FVC) scores above average. It has been proposed that this is the body's natural way to compensate for a loss of breathing depth.

Often patients have tight hamstrings, which, again, is related to the body compensating for excessive spinal curvature, though this is also debated (for example, some suggest the tightness of ligament is the initial cause of the growth abnormality). In addition to the common lordosis, it has been suggested that between 20–30% of patients with Scheuermann's Disease also have scoliosis, though most cases are negligible. In more serious cases, however, the combination is classified as a separate condition known as kyphoscoliosis.

A neutral spine or good posture refers to the "three natural curves [that] are present in a healthy spine." Looking directly at the front or back of the body, the 33 vertebrae in the spinal column should appear completely vertical. From a side view, the cervical (neck) region of the spine (C1-C7) is bent inward, the thoracic (upper back) region (T1-T12) bends outward, and the lumbar (lower back) region (L1-L5) bends inward. The sacrum (tailbone area) (S1-S5 fused) and coccyx (on average 4 fused) rest between the pelvic bones. A neutral pelvis indicates the anterior superior iliac spines and pubic symphysis fall in the same vertical line.

The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate, in which the notochord (a flexible rod of uniform composition) found in all chordates has been replaced by a segmented series of bones—vertebrae separated by intervertebral discs. The vertebral column houses the spinal canal, a cavity that encloses and protects the spinal cord.

There are about 50,000 species of animals that have a vertebral column. The human vertebral column is one of the most-studied examples.

Excessive or abnormal spinal curvature is classed as a spinal disease or dorsopathy and includes the following abnormal curvatures:

- Kyphosis is an exaggerated kyphotic (concave) curvature in the thoracic region, also called hyperkyphosis. This produces the so-called "humpback" or "dowager's hump", a condition commonly resulting from osteoporosis.

- Lordosis as an exaggerated lordotic (convex) curvature of the lumbar region, is known as lumbar hyperlordosis and also as "swayback". Temporary lordosis is common during pregnancy.

- Scoliosis, lateral curvature, is the most common abnormal curvature, occurring in 0.5% of the population. It is more common among females and may result from unequal growth of the two sides of one or more vertebrae, so that they do not fuse properly. It can also be caused by pulmonary atelectasis (partial or complete deflation of one or more lobes of the lungs) as observed in asthma or pneumothorax.

- Kyphoscoliosis, a combination of kyphosis and scoliosis.

These conditions nearly all present with an insidious onset of pain referred to the location of the bony damage. Some, notably Kienbock's disease of the wrist, may involve considerable swelling, and Legg-Calvé-Perthes disease of the hip causes the victim to limp. The spinal form, Scheuermann's disease, may cause bending, or kyphosis of the upper spine, giving a "hunch-back" appearance.

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.

Scoliosis is a common spinal disease in which the spine has a curvature usually in the shape of the letter "C" or "S". This is most common in girls, but there is no specific cause for scoliosis. Only a few symptoms occur for one with this disease, which include feeling tired in the spinal region or backaches. Generally, if the hips or shoulders are uneven, or if the spine curves, it is due to scoliosis and should be seen by a doctor.

Osteochondrosis is a family of orthopedic diseases of the joint that occur in children and adolescents and in rapidly growing animals, particularly pigs, horses, dogs, and broiler chickens. They are characterized by interruption of the blood supply of a bone, in particular to the epiphysis, followed by localized bony necrosis, and later, regrowth of the bone. This disorder is defined as a focal disturbance of endochondral ossification and is regarded as having a multifactorial cause, so no one thing accounts for all aspects of this disease.

A burst fracture is a type of traumatic spinal injury in which a vertebra breaks from a high-energy axial load (e.g., traffic collisions or falls from a great height or high speed, and some kinds of seizures), with shards of vertebra penetrating surrounding tissues and sometimes the spinal canal. The burst fracture is categorized by the ""severity of the deformity, the severity of" (spinal) "canal compromise, the degree of loss of vertebral body height, and the degree of neurologic deficit."" Burst fractures are considered more severe than compression fractures because long-term neurological damage can follow. The neurologic deficits can reach their full extent immediately, or can progress for a prolonged time.

Lumbar spinal stenosis is classified as a narrowing of the spinal canal in the lumbar region of the vertebrae. This may lead to compression of the nerve root of the spinal cord and result in pain of the lower back and lower extremities. Other symptoms include impaired walking and a slightly stooped posture due to loss of disc height and bulging of the disc. Lumbar spinal stenosis is very prevalent with 9.3% of the general population producing symptoms and the number is continuing to rise in patients older than 60. It's generally an indication for spinal surgery in patients older than 65 years of age.

The primary symptom of camptocormia is abnormal forward bending of the torso. This bending becomes worse while walking but does not appear when the affected individual is lying down in a horizontal position. This alleviation of the condition indicates that it is a manifestation of another disease or ailment and is not due to a spine that is actually bent. This is somewhat ironic, since the medically accepted name for the condition is bent spine syndrome.

In an afflicted individual, the abnormal bending consists of an anterior flexion greater than 45 degrees. Because of this bending and the physical limitations caused by the conditions associated with the disease, it is usually impossible for an afflicted person to achieve a fully erect position. In addition, patients suffering from camptocormia often experience low back pain as a result of the condition. BSS often appears in individuals afflicted with Parkinson’s disease, muscular dystrophies, endocrine disorders, inflammatory conditions (myositis), or mitochondrial myopathies. As previously mentioned, the disease is more common in older individuals.

Transitional vertebrae have the characteristics of two types of vertebra. The condition usually involves the vertebral arch or transverse processes. It occurs at the cervicothoracic, thoracolumbar, or lumbosacral junction. For instance, the transverse process of the last cervical vertebra may resemble a rib. A transitional vertebra at the lumbosacral junction can cause arthritis, disk changes, or spinal cord compression. Back pain associated with lumbosacral transitional vertebrae (LSTV) is known as Bertolotti's syndrome. One study found that male German Shepherd Dogs with a lumbosacral transitional vertebra are at greater risk for cauda equina syndrome, which can cause rear limb weakness and incontinence.

Scoliosis is well established and even evaluated at an early age. It is typically quantified using the standardized Cobb angle method. This method consists of measuring the degree of deformity by the angle between two successive vertebrae. The Cobb method was accepted by the Scoliosis Research Society (SRS) in 1966. It serves as the standard method for quantification of scoliosis deformities. Sagittal plane posture aberrations such as cervical and lumbar lordosis and thoracic kyphosis have yet to be quantified due to considerable inter-individual variability in normal sagittal curvature. The Cobb method was also one of the first techniques used to quantify sagittal deformity. As a 2D measurement technique it has limitations and new techniques are being proposed for measurement of these curvatures. Most recently, 3D imaging techniques using computed tomography (CT) and magnetic resonance (MR) have been attempted. These techniques are promising but lack the reliability and validity necessary to be used as a reference for clinical purposes.

Posture assessment has also become quite popular in many practical environments like the personal training and sports conditioning settings. The need for reliable methods of posture assessment as a screening tool is warranted. Current available programs such as those through the National Posture Institute (NPI) and Posture Print are recommended for the practical setting but cost close to $1000 and are clearly a profiteering scam by individuals not at all concerned with human well-being.

Chronic deviations from neutral spine lead to improper posture, increased stress on the back and causes discomfort and damage. People who sit for long hours on the job are susceptible to a number of misalignments.

"Neutral spine" is ideally maintained while sitting, standing, and sleeping.

Symptoms reported by sufferers include: pain and aching to the neck and back, referred pain to the shoulders, sensory disturbance (such as pins and needles) to the arms and legs, and headaches. Symptoms can appear directly after the injury, but often are not felt until days afterwards. Whiplash is usually confined to the spine. The most common areas of the spine affected by whiplash are the neck and middle of the spine. "Neck" pain is very common between the shoulder and the neck. The "missing link" of whiplash may be towards or inside the shoulder and this would explain why neck therapy alone frequently does not give lasting relief.

Cognitive symptoms following whiplash trauma, such as being easily distracted or irritated, seems to be common and possibly linked to a poorer prognosis.

BSS is not limited to the elderly but has an average age of onset of 66 years and is more common amongst men. This late age of onset is largely due to the increased preponderance of the conditions causing the symptom in older individuals – such as muscular weakness and neurological disorders like Parkinson's disease. While BSS doesn’t have any negative stigma in and of itself, those affected by it may be perceived differently due to the condition. For example, an elderly individual afflicted with the condition may be viewed as very physically weak, because of the severe bending of the back caused by the condition.