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.

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.

Normal lordotic curvatures, also known as "secondary" curvatures, result in a difference in the thickness between the front and back parts of the intervertebral disc. Lordosis may also increase at puberty, sometimes not becoming evident until the early or mid-20s.

In radiology, a "lordotic view" is an X-ray taken of a patient leaning backward.

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.

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

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.

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.

Understanding the meaning of signs and symptoms for the clinical syndrome of lumbar stenosis requires an understanding of what the syndrome is, and the prevalence of the condition. A recent review on lumbar stenosis in the Journal of the American Medical Association's "Rational Clinical Examination Series" emphasized that the syndrome can be considered when lower extremity pain occurs in combination with back pain. This syndrome occurs in 12% of older community dwelling men and up to 21% of those in retirement communities.

The leg symptoms in lumbar spinal stenosis (LSS) are similar to those found with vascular claudication, giving rise to the term pseudoclaudication. These symptoms include pain, weakness, and tingling of the legs, which may radiate down the leg to the feet. Additional symptoms in the legs may be fatigue, heaviness, weakness, a sensation of tingling, pricking, or numbness and leg cramps, as well as bladder symptoms. Symptoms are most commonly bilateral and symmetrical, but they may be unilateral; leg pain is usually more troubling than back pain.

Pseudoclaudication, now referred to as neurogenic claudication, typically worsen with standing or walking and improve with sitting. The occurrence is often related to posture and lumbar extension. Lying on the side is often more comfortable than lying flat, since it permits greater lumbar flexion. Vascular claudication can resemble spinal stenosis, and some individuals experience unilateral or bilateral symptoms radiating down the legs rather than true claudication.

The first symptoms of stenosis include bouts of low back pain. After a few months or years, this may progress to claudication. The pain may be radicular, following the classic neurologic pathways. This occurs as the spinal nerves or spinal cord become increasingly trapped in a smaller space within the canal. It can be difficult to determine whether pain in the elderly is caused by lack of blood supply or stenosis; testing can usually differentiate between them but patients can have both vascular disease in the legs and spinal stenosis.

Among people with lower extremity pain in combination with back pain, lumbar stenosis as the cause is two times more likely in those older than 70 years of age while those younger than 60 years it is 0.40 as likely. The character of the pain is also useful. When the discomfort does not occur while seated, the likelihood of LSS increases considerably around 7.4 times. Other features increasing the likelihood of lumbar stenosis are improvement in symptoms on bending forward 6.4 times, pain that occurs in both buttocks or legs 6.3 times, and the presence of neurogenic claudication 3.7 times. Alternately, the absence of neurogenic claudication makes lumbar stenosis much less likely as the explanation for the pain.

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.

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.

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.

Lumbar spinal stenosis (LSS) is a medical condition in which the spinal canal narrows and compresses the nerves at the level of the lumbar vertebrae. This is usually due to the common occurrence of spinal degeneration that occurs with aging. It can also sometimes be caused by spinal disc herniation, osteoporosis, a tumor, or trauma. In the cervical (neck) and lumbar (low back) region it can be a congenital condition to varying degrees.

It is also a common symptom for those who suffer from various skeletal dysplasias such as with pseudoachondroplasia and achondroplasia at an early age.

Spinal stenosis may affect the cervical or thoracic region in which case it is known as cervical spinal stenosis or thoracic spinal stenosis. In some cases, it may be present in all three places in the same patient. Lumbar spinal stenosis can cause low back pain, abnormal sensations, and the absence of sensation (numbness) in the legs, thighs, feet or buttocks, or loss of bladder and bowel control.

The signs and symptoms of diastematomyelia may appear at any time of life, although the diagnosis is usually made in childhood. Cutaneous lesions (or stigmata), such as a hairy patch, dimple, Hemangioma, subcutaneous mass, Lipoma or Teratoma override the affected area of the spine is found in more than half of cases. Neurological symptoms are nonspecific, indistinguishable from other causes of cord tethering. The symptoms are caused by tissue attachments that limit the movement of the spinal cord within the spinal column. These attachments cause an abnormal stretching of the spinal cord.

The course of the disorder is progressive. In children, symptoms may include the "stigmata" mentioned above and/or foot and spinal deformities; weakness in the legs; low back pain; scoliosis; and incontinence. In adulthood, the signs and symptoms often include progressive sensory and motor problems and loss of bowel and bladder control. This delayed presentation of symptoms is related to the degree of strain placed on the spinal cord over time.

Tethered spinal cord syndrome appears to be the result of improper growth of the neural tube during fetal development, and is closely linked to spina bifida.

Tethering may also develop after spinal cord injury and scar tissue can block the flow of fluids around the spinal cord. Fluid pressure may cause cysts to form in the spinal cord, a condition called syringomyelia. This can lead to additional loss of movement, feeling or the onset of pain or autonomic symptoms.

Cervical diastematomyelia can become symptomatic as a result of acute trauma, and can cause major neurological deficits, like hemiparesis, to result from otherwise mild trauma.

The following definitions may help to understand some of the related entities:

- Diastematomyelia (di·a·stem·a·to·my·elia) is a congenital anomaly, often associated with spina bifida, in which the spinal cord is split into halves by a bony spicule or fibrous band, each half being surrounded by a dural sac.

- Myeloschisis (my·elos·chi·sis) is a developmental anomaly characterized by a cleft spinal cord, owing to failure of the neural plate to form a complete neural tube or to rupture of the neural tube after closure.

- Diplomyelia (diplo.my.elia) is a true duplication of spinal cord in which these are two dural sacs with two pairs of anterior and posterior nerve roots.

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.

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)

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.

In children, symptoms may include:

- Lesions, hairy patches, dimples, or fatty tumours on the lower back

- Foot and spinal deformities

- Weakness in the legs (loss of muscle strength and tone)

- Change in or abnormal gait including awkwardness while running or wearing the tips or side of one shoe

- Low back pain

- Scoliosis (abnormal curvature of the spine to the left or right)

- Urinary irregularities (incontinence or retention)

Tethered spinal cord syndrome may go undiagnosed until adulthood, when sensory, motor, bowel, and bladder control issues emerge. This delayed presentation of symptoms relates to the degree of strain on the spinal cord over time.

Tethering may also develop after spinal cord injury. Scar tissue can block the flow of fluids around the spinal cord. Fluid pressure may cause cysts to form in the spinal cord, a condition called syringomyelia. This can lead to additional loss of movement or feeling, or the onset of pain or autonomic nervous system symptoms.

In adults, onset of symptoms typically include:

- Severe pain (in the lower back and radiating into the legs, groin, and perineum)

- Bilateral muscle weakness and numbness

- Loss of feeling and movement in lower extremities

- Urinary irregularities (incontinence or retention)

- Bowel control issues

Neurological symptoms can include a mixed picture of upper and lower motor neuron findings, such as amyotrophy, hyperreflexia, and pathologic plantar response, occurring in the same limb. Profound sensory changes, such as loss of pain, temperature, and proprioceptive sensations, are common. Last, progressive symptoms of a neuropathic bladder are noted on over 70% of adult patients, versus only 20% to 30% of children. These symptoms include urinary frequency and urgency, feeling of incomplete voiding, poor voluntary control, and urge and stress incontinence. Chronic recurrent infections are common and occasionally lead to nephrolithiasis (kidney stones), renal failure, or renal transplantation. Female patients also give a history of ineffective labor and postpartum rectal prolapse, presumably due to an atonic pelvic floor.

Vertebral fractures of the thoracic vertebrae, lumbar vertebrae or sacrum are usually associated with major trauma and can cause spinal cord injury that results in a neurological deficit.

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.

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.

A spinal fracture, also called a vertebral fracture or a broken back, is a fracture affecting the vertebrae of the spinal column. Most types of spinal fracture confer a significant risk of spinal cord injury. After the immediate trauma, there is a risk of spinal cord injury (or worsening of an already injured spine) if the fracture is "unstable", that is, likely to change alignment without internal or external fixation.

Diastematomyelia (occasionally diastomyelia) is a congenital disorder in which a part of the spinal cord is split, usually at the level of the upper lumbar vertebra.

Diastematomyelia is a rare congenital anomaly that results in the "splitting" of the spinal cord in a longitudinal (sagittal) direction. Females are affected much more commonly than males. This condition occurs in the presence of an osseous (bone), cartilaginous or fibrous septum in the central portion of the spinal canal which then produces a complete or incomplete sagittal division of the spinal cord into two hemicords. When the split does not reunite distally to the spur, the condition is referred to as a diplomyelia, or true duplication of the spinal cord.

Tethered spinal cord can be caused by various conditions but the main cause is when tissue attachments limit the movement of the spinal cord in the spinal column which causes abnormal stretching of the cord. The tethered spinal cord syndrome is correlated with having the causes:

- Spina bifida

- Occulta

- Mylomeningocele

- Meningocele

- History of spinal trauma

- History of spinal surgery

- Tumor(s) in the spinal column

- Thickened and/or tight filum terminale

- Lipoma(s) in the spinal column

- Dermal Sinus Tract (congenital deformity)

- Diastematomyelia (split spinal cord)

Tethered spinal cord is a disorder and not a mechanism so it does not spread to other people and there are no measures that can be done to prevent it beforehand. The only preventative measure that is successful is to surgically untether the spinal cord though there might already be irreversible damage.