The cause is not currently known, and the condition appears to be multifactorial. Several candidate genes (such as FBN1, which has been associated with Marfan) have been proposed and excluded.

The risk of serious complications from spinal fusion surgery for kyphosis is estimated to be 5%, similar to the risks of surgery for scoliosis. Possible complications include inflammation of the soft tissue or deep inflammatory processes, breathing impairments, bleeding, and nerve injuries. According to the latest evidence, the actual rate of complications may be substantially higher. Even among those who do not suffer from serious complications, 5% of patients require reoperation within five years of the procedure, and in general it is not yet clear what one would expect from spine surgery during the long-term. Taking into account that signs and symptoms of spinal deformity cannot be changed by surgical intervention, surgery remains to be a cosmetic indication. Unfortunately, the cosmetic effects of surgery are not necessarily stable.

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.

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.

Sprengel's deformity (also known as high scapula or congenital high scapula) is a rare congenital skeletal abnormality where a person has one shoulder blade that sits higher on the back than the other. The deformity is due to a failure in early fetal development where the shoulder fails to descend properly from the neck to its final position. The deformity is commonly associated with other conditions, most notably Klippel-Feil syndrome, congenital scoliosis including cervical scoliosis, fused ribs, the presence of an omovertebral bone and spina bifida. The left shoulder is the most commonly affected shoulder but the condition can be bilateral, meaning that both shoulders are affected. About 75% of all observed cases are girls. Treatment includes surgery in early childhood and physical therapy. Surgical treatment in adulthood is complicated by the risk of nerve damage when removing the omovertebral bone and when stretching the muscle tissue during relocation of the shoulder.

Pectus excavatum occurs in an estimated 1 in 150 to 1 in 1000 births, with male predominance (male-to-female ratio of 3:1). In 35% to 45% of cases family members are affected.

Researchers are unsure of the cause of pectus excavatum but assume that there is a genetic component for at least some of the cases as 37% of individuals have an affected first degree family member. As of 2012, a number of genetic markers for pectus excavatum have also been discovered.

Pectus excavatum is a relatively common symptom of Noonan syndrome, Marfan syndrome and Loeys-Dietz syndrome and sometimes is found in other connective tissue disorders such as Ehlers–Danlos Syndrome. Many children with spinal muscular atrophy develop pectus excavatum due to their diaphragmatic breathing. Pectus excavatum also occurs in about 1% of persons diagnosed with celiac disease for unknown reasons.

The scapula is small and rotated so that its inferior edge points toward the spine. There is a high correlation between Sprengel's deformity and the Klippel-Feil syndrome. Sometimes a bony connection is present between the elevated scapula and one of the cervical vertebrae, usually C5 or C6. This connection is known as the omovertebral bone.

Presence at birth is extremely rare and associated with other congenital anomalies such as proximal femoral focal deficiency, fibular hemimelia or anomalies in other part of the body such as cleidocranial dyastosis. The femoral deformity is present in the subtrochantric area where the bone is bent. The cortices are thickened and may be associated with overlying skin dimples. External rotation of the femur with valgus deformity of knee may be noted. This condition does not resolve and requires surgical management. Surgical management includes valgus osteotomy to improve hip biomechanics and length and rotational osteotomy to correct retroversion and lengthening.

In most cases persisting after childhood, there is little or no effect on the ability to walk. Due to uneven stress and wear on the knees, however, even milder manifestations can see an accelerated onset of arthritis.

Coxa vara is a deformity of the hip, whereby the angle between the head and the shaft of the femur is reduced to less than 120 degrees. This results in the leg being shortened, and the development of a limp. It is commonly caused by injury, such as a fracture. It can also occur when the bone tissue in the neck of the femur is softer than normal, causing it to bend under the weight of the body. This may either be congenital or the result of a bone disorder. The most common cause of coxa vara is either congenital or developmental. Other common causes include metabolic bone diseases (e.g. Paget's disease of bone), post-Perthes deformity, osteomyelitis, and post traumatic (due to improper healing of a fracture between the greater and lesser trochanter). Shepherd's Crook deformity is a severe form of coxa vara where the proximal femur is severely deformed with a reduction in the neck shaft angle beyond 90 degrees. It is most commonly a sequela of osteogenesis imperfecta, Pagets disease, osteomyelitis, tumour and tumour-like conditions (e.g. fibrous dysplasia).

Coxa vara can happen in cleidocranial dysostosis.

A common cause is the supracondylar fracture of humerus. It can be corrected via a corrective osteotomy of the humerus and either internal or external fixation of the bone until union.

Coxa valga is a deformity of the hip where the angle formed between the head and neck of the femur and its shaft is increased, usually above 135 degrees. It is caused by a slipped epiphysis of the femoral head.

The differential diagnosis includes neuromuscular disorders (i.e. cerebral palsy, spinal dysraphism, poliomyelitis), skeletal dysplasias, and juvenile idiopathic arthritis.

Leri-Weill dyschondrosteosis is a pseudoautosomal dominant disorder which occurs more frequently in females and is due to a mutation, deletion or duplication of the SHOX gene. The SHOX gene plays a particularly important role in the growth and maturation of bones in the arms and legs. The SHOX gene is located within band Xp22.3 of the pseudoautosomal region of the X chromosome, which escapes X-inactivation. Homozygous SHOX gene mutations result in Langer mesomelic dysplasia.

Colles fractures occur in all age groups, although certain patterns follow an age distribution.

- In the elderly, because of the weaker cortex, the fracture is more often extra-articular.

- Younger individuals tend to require a higher energy force to cause the fracture and tend to have more complex intra-articular fractures. In children with open epiphyses, an equivalent fracture is the "epiphyseal slip", as can be seen in other joints, such as a slipped capital femoral epiphysis in the hip. This is a Salter I or II fracture with the deforming forces directed through the weaker epiphyseal plate.

- More common in women because of post-menopausal osteoporosis.

A cubitus varus deformity is more cosmetic than limiting of any function, however internal rotation of the radius over the ulna may be limited due to the overgrowth of the humerus. This may be noticeable during an activity such as using a computer mouse.

If a child is sickly, either with rickets or any other ailment that prevents ossification of the bones, or is improperly fed, the bowed condition may persist. Thus the chief cause of this deformity is rickets. Skeletal problems, infection, and tumors can also affect the growth of the leg, sometimes giving rise to a one-sided bow-leggedness. The remaining causes are occupational, especially among jockeys, and from physical trauma, the condition being very likely to supervene after accidents involving the condyles of the femur.

Distal radius fractures are the most common fractures seen in adults, with incidence in females outnumbering incidence in males by a factor of 2-3. Men who sustain distal radius fractures are usually younger, generally in their fifth decade (vs. seventh decade in females). The elderly are more susceptible because of the osteopenia and osteoporosis commonly seen in this age group. The majority of these fractures are extra-articular (i.e. not involving the joint).

This is also a common injury in children which may involve the growth plate (Salter-Harris fracture).

In young adults, the injury is often severe as a greater force is necessary to produce the injury.

The cause of fibular hemimelia is unclear. Purportedly, there have been some incidents of genetic distribution in a family; however, this does not account for all cases. Maternal viral infections, embryonic trauma, teratogenic environmental exposures or vascular dysgenesis (failure of the embryo to form a satisfactory blood supply) between four and seven weeks gestation are considered possible causes.

In an experimental mouse model, change in the expression of a homeobox gene led to similar, but bilateral, fibular defects.

It is a congenital subluxation or dislocation of the ulna's distal end, due to malformation of the bones. Sometimes, minor abnormalities of other bone structures, often caused by disease or injury, such as a fracture of the distal end of the radius with upward displacement of the distal fragment. The deformity varies in degree from a slight protrusion of the lower end of the ulna, to complete dislocation of the inferior radio-ulnar joint with marked radial deviation of the hand. Severe deformities are associated with congenital absence or hypoplasia of the radius.

The male:female rate of this disorder is 1:4. The incidence is unknown, and there is no described racial predominance. Even though Madelung's Deformity is considered a congenital disorder, symptoms sometimes aren't seen until adulthood. In most cases, symptoms find their onset during midchildhood. At this age, the relatively slower growth of the ulnar and palmar part of the radius, leads to an increasingly progressive deformity. Pain and deformity are the main symptoms patients present with. Typical clinical presentation consists of a short forearm, anterior-ulnar bow of the radius and a forward subluxation of the hand on the forearm. As mentioned before, the severity of the disorder varies greatly, which also leads to a spectrum of presentation.

Physiologically, increased pressure "in utero", rickets and increased traction on the sternum due to abnormalities of the diaphragm have been postulated as specific mechanisms. Because the heart is located behind the sternum, and because individuals with pectus excavatum have been shown to have visible deformities of the heart seen both on radiological imaging and after autopsies, it has been hypothesized that there is impairment of function of the cardiovascular system in individuals with pectus excavatum. While some studies have demonstrated decreased cardiovascular function, no consensus has been reached based on newer physiological tests such as echocardiography of the presence or degree of impairment in cardiovascular function. Similarly, there is no consensus on the degree of functional improvement after corrective surgery; A 2013 meta-analysis yielded conflicting results.

The following factors may be involved in causing this deformity:

- Inherent laxity of the knee ligaments

- Weakness of biceps femoris muscle

- Instability of the knee joint due to ligaments and joint capsule injuries

- Inappropriate alignment of the tibia and femur

- Malunion of the bones around the knee

- Weakness in the hip extensor muscles

- Gastrocnemius muscle weakness (in standing position)

- Upper motor neuron lesion (for example, hemiplegia as the result of a cerebrovascular accident)

- Lower motor neuron lesion (for example, in post-polio syndrome)

- Deficit in joint proprioception

- Lower limb length discrepancy

- Congenital genu recurvatum

- Cerebral palsy

- Multiple sclerosis

- Muscular dystrophy

- Limited dorsiflexion (plantar flexion contracture)

- Popliteus muscle weakness

- Connective tissue disorders. In these disorders, there are excessive joint mobility (joint hypermobility) problems. These disorders include:

- Marfan syndrome

- Ehlers-Danlos syndrome

- Benign hypermobile joint syndrome

- Osteogenesis imperfecta disease

Clinodactyly (from the Ancient Greek κλίνειν ' meaning "to bend" and δάκτυλος ' meaning "digit") is a medical term describing the curvature of a digit (a finger or toe) in the plane of the palm, most commonly the fifth finger (the "little finger") towards the adjacent fourth finger (the "ring finger").

It is a fairly common isolated anomaly which often goes unnoticed, but also occurs in combination with other abnormalities in certain genetic syndromes.

Femoroacetabular Impingement (FAI), or hip impingement syndrome, may affect the hip joint in young and middle-aged adults and occurs when the ball shaped femoral head rubs abnormally or does not permit a normal range of motion in the acetabular socket. Damage can occur to the articular cartilage, or labral cartilage (soft tissue bumper of the socket), or both. Treatment options range from conservative to arthroscopic to open surgery.

In children the outcome of distal radius fracture treatment in casts is usually very successful with healing and return to normal function expected. Some residual deformity is common but this often remodels as the child grows. In the elderly, distal radius fractures heal and may result in adequate function following non-operative treatment. A large proportion of these fractures occur in elderly people that may have less requirement for strenuous use of their wrists. Some of these patients tolerate severe deformities and minor loss of wrist motion very well even without reduction of the fracture. In this low demand group only a short period of immobilization is indicated as rapid mobilization improves functional outcome.

In younger patients the injury requires greater force and results in more displacement particularly to the articular surface. Unless an accurate reduction of the joint surface is obtained, these patients are very likely to have long term symptoms of pain, arthritis, and stiffness.