This is a very rare situation, in which the extra digit is on the ring, middle or index finger. Of these fingers, the index finger is most often affected, whereas the ring finger is rarely affected.

This type of polydactyly can be associated with syndactyly, cleft hand and several syndromes.

Polysyndactyly presents various degrees of syndactyly affecting fingers three and four.

The triphalangeal thumb has a different appearance than normal thumbs. The appearance can differ widely; the thumb can be a longer thumb, it can be deviated in the radio-ulnar plane (clinodactyly), thumb strength can be diminished. In the case of a five fingered-hand it has a finger-like appearance, with the position in the plane of the four fingers, thenar muscle deficiency, and additional length. There is often a combination with radial polydactyly.

This is a less common situation, in which the affectation is on the side of the hand towards the thumb. Radial polydactyly refers to the presence of an extra digit (or extra digits) on the radial side of the hand. It is most frequent in Indian populations and it is the second most common congenital hand disorder. The incidence of radial polydactyly is reported as 1 in every 3,000 live births. The clinical features of radial polydactyly will depend upon the extent of duplication.

Radial polydactyly varies from a barely visible radial skin tag to complete duplication. Thumb polydactyly varies from barely visible broadening of the distal phalanx to full duplication of the thumb including the first metacarpal.

Radial polydactyly is frequently associated with several syndromes.

Oligodactyly (from the Ancient Greek "oligos" meaning "few" and δάκτυλος "daktylos" meaning "finger") is the presence of fewer than five fingers or toes on a hand or foot.

It is quite often incorrectly called "hypodactyly", but the Greek prefixes and are used for scales (e.g. in hypoglycaemia and hypercholesterolemia). This as opposed to or scales, where and should be used (e.g. in oligarchy and polygamy). Oligodactyly is therefore the opposite of polydactyly. Very rare, this medical condition usually has a genetic or familial cause.

Oligodactyly is sometimes a sign or symptom of several syndromes including Poland syndrome and Weyer Ulnar Ray Syndrome. It is a type of Dysmelia.

Ectrodactyly is an extreme instance of oligodactyly, involving the absence of one or more central digits of the hand or foot and is also known as split hand/split foot malformation (SHFM). The hands and feet of people with ectrodactyly are often described as "claw-like" and may include only the thumb and one finger (usually either the little finger, ring finger, or a syndactyly of the two) with similar abnormalities of the feet.

People with oligodactyly often have full use of the remaining digits and adapt well to their condition. They are not greatly hindered in their daily activities, if at all. Even those with the most extreme forms are known to engage in tasks that require fine control, such as writing and bootmaking as well as working as a cab driver.

Vadoma people of Zimbabwe have a high frequency of oligodactyly.

Generally, triphalangeal thumbs are non-opposable. In contrast to most people with opposable thumbs, a person suffering from TPT cannot easily place his or her thumb opposite the other four digits of the same hand. The opposable thumb's ability to effortlessly utilize fingers in a "pinch" formation is critical in precision gripping. For the thumb to adequately grip, certain thumb criteria must be met (e.g. suitable position and length, stable joints and good thenar muscle strength). Because triphalangeal thumbs cannot easily oppose and do not possess many of the optimal qualities found in most opposable thumbs, they tend to cause the hand to be less effective in use and, therefore, prove to be more problematic in daily life.

Ectrodactyly, split hand, cleft hand, derived from the Greek "ektroma" (abortion) and "daktylos" (finger) involves the deficiency or absence of one or more central digits of the hand or foot and is also known as split hand/split foot malformation (SHFM). The hands and feet of people with ectrodactyly are often described as "claw-like" and may include only the thumb and one finger (usually either the little finger, ring finger, or a syndactyly of the two) with similar abnormalities of the feet.

It is a rare form of a congenital disorder in which the development of the hand is disturbed. It is a type I failure of formation – longitudinal arrest. The central ray of the hand is affected and usually appears without proximal deficiencies of nerves, vessels, tendons, muscles and bones in contrast to the radial and ulnar deficiencies. The cleft hand appears as a V-shaped cleft situated in the centre of the hand. The digits at the borders of the cleft might be syndactilyzed, and one or more digits can be absent. In most types, the thumb, ring finger and little finger are the less affected parts of the hand. The incidence of cleft hand varies from 1 in 90,000 to 1 in 10,000 births depending on the used classification. Cleft hand can appear unilateral or bilateral, and can appear isolated or associated with a syndrome.

Split hand/foot malformation (SHFM) is characterized by underdeveloped or absent central digital rays, clefts of hands and feet, and variable syndactyly of the remaining digits. SHFM is a heterogeneous condition caused by abnormalities at one of multiple loci, including SHFM1 (SHFM1 at 7q21-q22), SHFM2 (Xq26), SHFM3 (FBXW4/DACTYLIN at 10q24), SHFM4 (TP63 at 3q27), and SHFM5 (DLX1 and DLX 2 at 2q31). SHFM3 is unique in that it is caused by submicroscopic tandem chromosome duplications of FBXW4/DACTYLIN. SHFM3 is considered 'isolated' ectrodactyly and does not show a mutation of the tp63 gene.

Dysmelia (from Gr. δυσ- "dys", "bad" + μέλ|ος "mél|os", "limb" + Eng. suff. -ia) is a congenital disorder of a limb resulting from a disturbance in embryonic development.

Diplopodia is a congenital anomaly in tetrapods that involves duplication of elements of the foot on the hind limb. It comes from the Greek roots diplo = "double" and pod = "foot". Diplopodia is often found in conjunction with other structural abnormalities and can be lethal. It is more extreme than polydactyly, the presence of extra digits.

Specific types of additional body parts include:

- Accessory breast – one or more additional breasts

- Accessory spleen – one or more additional spleens

- Cervical rib – an additional rib

- Diphallia - Having two penes/penises.

- Hermaphroditism – having both sexes' sex organs

- Hyperdontia – additional teeth

- Pelvic digit – a bony growth in the soft tissue of the pelvic region

- Polycephaly – an extra head

- Polydactyly – additional fingers or toes

- Polymelia — an extra arm or leg.

- Polyorchidism – having three or more testicles

- Supernumerary bones – these additional bones are fairly common, particularly in the feet, and are frequently mistaken for fractures on x-rays.

- Supernumerary kidney – a third kidney

- Supernumerary nipples – an additional nipple

- Supernumerary phantom limbs – where the brain acts as though a limb were there, but it is not.

- Syndactyly – webbing between the fingers or toes

- Uterus didelphys – two vaginal canals and/or uteri

In clubfoot one or both feet are rotated inwards and downwards. The affected foot, calf, and leg may be smaller than the other. In about half of those affected, both feet are involved. Most cases are not associated with other problems. Without treatment, people walk on the sides of their feet which causes issues with walking.

A squitten is a cat with unusually short forelegs and/or unusually long hind legs that resembles a squirrel. It is an example of a cat body type genetic mutation. The word is a portmanteau of squirrel and kitten.

The term kangaroo cat is also, rarely, used; this derives from a 1953 specimen known as the Stalingrad Kangaroo Cat.

Synpolydactyly is a joint presentation of syndactyly (fusion of digits) and polydactyly (production of supernumerary digits). This is often a result of a mutation in the HOX D13 gene.

Types include:

Dysmelia can refer to

- missing (aplasia) limbs: amelia, oligodactyly, congenital amputation e.g. Tibial or Radial aplasia

- malformation of limbs: shortening (micromelia, rhizomelia or mesomelia), ectrodactyly, phocomelia, meromelia, syndactyly, brachydactyly, club foot

- too many limbs: polymelia, polydactyly, polysyndactyly

- others: Tetraamelia, hemimelia, Symbrachydactyly

Rocker bottom foot, also known as congenital vertical talus, is an anomaly of the foot. It is characterized by a prominent calcaneus (heel bone) and a convex rounded bottom of the foot. It gets its name from the foot's resemblance to the bottom of a rocking chair.

It can be associated with Edwards' syndrome (trisomy 18), Patau syndrome (trisomy 13), Trisomy 9 and mutation in the gene HOXD10.

It can also be associated with Charcots foot.

Congenital limb deformities are congenital musculoskeletal disorders which primarily affect the upper and lower limbs.

An example is polydactyly.

The Wassel classification is used to categorise radial polydactyly, based upon the most proximal level of skeletal duplication.

Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs.

Many additional body parts form by the same process as conjoined twins: the zygote begins to split but fails to completely separate. This condition may also be a symptom of repeated occurrences of continuous inbreeding in a genetic line.

There are several classifications for cleft hand, but the most used classification is described by Manske and Halikis see table 3. This classification is based on the first web space. The first web space is the space between the thumb and the index.

Table 3: Classification for cleft hand described by Manske and Halikis

Clubfoot is a birth defect where one or both feet are rotated inwards and downwards. The affected foot, calf, and leg may be smaller than the other. In about half of those affected, both feet are involved. Most cases are not associated with other problems. Without treatment, people walk on the sides of their feet which causes issues with walking.

The exact cause is usually unclear. A few cases are associated with distal arthrogryposis or myelomeningocele. If one identical twin is affected there is a 33% chance the other one will be as well. Diagnosis may occur at birth or before birth during an ultrasound exam.

Initial treatment is most often with the Ponseti method. This involves moving the foot into an improved position followed by casting, which is repeated at weekly intervals. Once the inward bending is improved, the Achilles tendon is often cut and braces are worn until the age of four. Initially the brace is worn nearly continuously and then just at night. In about 20% of cases further surgery is required.

Clubfoot occurs in about one in 1,000 newborns. The condition is less common among the Chinese and more common among Maori. Males are affected about twice as often as females. Treatment can be carried out by a range of healthcare providers and can generally be achieved in the developing world with few resources.

The term squitten is generally used to refer to cats with the condition radial hypoplasia (underdeveloped radius bones) or foreleg micromelia (small forelegs) and related conditions known as radial aplasia (absent radius bones), radial agenesis (failure of radius bones to form) that produces stunted forelegs. The mutation sometimes occurs in the random-breeding population, particularly in inbred populations where recessive genes may be exhibited. Such cats have also been called twisty cats; In the late 1990s, several were deliberately bred at Karma Farms, a horse farm and cattery in Marshall, Texas, resulting in a public outcry against the operators of the farm.

Radial hypoplasia is related to one form of polydactyly, sometimes called patty feet or hamburger feet by cat lovers to distinguish them from thumb cat polydactyls. Ordinary mitten cat polydactyls are not affected.

Cats with radial hypoplasia or similar mutations often sit on their rump with their forelegs unable to touch the floor; this gives them a resemblance to a squirrel or kangaroo. This raises special care considerations for owners of affected cats. Kittens may be unable to knead effectively with their short forelegs; kneading is required to stimulate milk flow in the mother. The short or twisted forelegs cause mobility problems and such cats may adapt by using their hindlegs in a hopping gait.

A corresponding condition affecting the hind legs is called femoral hypoplasia and has only been reported three times in cats.

Typical characteristics of a squitten are short forelegs, with a short radius and ulna which may be twisted or absent, extra front toes, and normal-length hind legs.

Polysyndactyly is an hereditary anatomical malformation combining polydactyly and syndactyly. There is also a type called "crossed" polysyndactyly

An equinovalgus is a deformity of the human foot. It may be a flexible deformity or a fixed deformity. Equino- means plantarflexed (as in standing on one's toes), and valgus means that the base of the heel is rotated away from the midline of the foot (eversion) and abduction of foot. This means that the patient is placing his/her weight on the medial border of the foot, and the arch of the foot is absent, which distorts the foot's normal shape.

Equinovalgus mostly occurs due to tightness of plantar flexors (calf muscles) and peroneus group of muscles.

The Pai Syndrome is a rare subtype of frontonasal dysplasia. It is a triad of developmental defects of the face, comprising midline cleft of the upper lip, nasal and facial skin polyps and central nervous system lipomas. When all the cases are compared, a difference in severity of the midline cleft of the upper lip can be seen. The mild form presents with just a gap between the upper teeth. The severe group presents with a complete cleft of the upper lip and alveolar ridge.

Nervous system lipomas are rare congenital benign tumors of the central nervous system, mostly located in the medial line and especially in the corpus callosum. Generally, patients with these lipomas present with strokes. However, patients with the Pai syndrome don’t. That is why it is suggested that isolated nervous system lipomas have a different embryological origin than the lipomas present in the Pai syndrome. The treatment of CNS lipomas mainly consists of observation and follow up.

Skin lipomas occur relatively often in the normal population. However, facial and nasal lipomas are rare, especially in childhood. However, the Pai syndrome often present with facial and nasal polyps. These skin lipomas are benign, and are therefore more a cosmetic problem than a functional problem.

The skin lipomas can develop on different parts of the face. The most common place is the nose. Other common places are the forehead, the conjunctivae and the frenulum linguae. The amount of skin lipomas is not related to the severity of the midline clefting.

Patients with the Pai syndrome have a normal neuropsychological development.

Until today there is no known cause for the Pai syndrome.

The large variety in phenotypes make the Pai syndrome difficult to diagnose. Thus the incidence of Pai syndrome seems to be underestimated.

The affected leg usually has one foot that is in an approximately normal position. The extra foot is composed of at least some metatarsal or tarsal bones and extra digits, though it is usually not complete. The feet can be joined together, so that the limb appears to have one large foot, or the extra foot can be joined to the limb separately, usually above the level of the other foot. Diplopodia affects one or both of the hind limbs.

On weightbearing projectional radiography, pes cavus can be diagnosed and graded by several features, the most important being medial peritalar subluxation, increased calcaneal pitch (variable) and abnormal "talar-1st metatarsal angle" (Meary's angle). Medial peritalar subluxation can be demonstrated by a medially rotated talonavicular coverage angle.