Characteristics are:

- A fibrous band instead of the fibula

- Short deformed leg

- Absence of the lateral part of the ankle joint (due to absence of the distal end of the fibula), and what is left is unstable; the foot has an equinovalgus deformity

- Possible absence of part of the foot requiring surgical intervention to bring the foot into normal function, or amputation.

- Possible absence of one or two toes on the foot

- Possible conjoined toes or metatarsals

Partial or total absence of fibula is among the most frequent limb anomalies. It is the most common long bone deficiency and is the most common skeletal deformity in the leg. It most often is unilateral (present only on one side). It may also present as bilateral (affecting both legs). Paraxial fibular hemimelia is the most common manifestation in which only the postaxial portion of the limb is affected. It is commonly seen as a complete terminal deficiency, where the lateral rays of the foot are also affected. Hemimelia can also be intercalary in which case the foot remains unaffected. Although the missing bone is easily identified, this condition is not simply a missing bone. Males are affected twice as often as females in most series.

Fibular hemimelia or longitudinal fibular deficiency is "the congenital absence of the fibula and it is the most common congenital absence of long bone of the extremities." It is the shortening of the fibula at birth, or the complete lack thereof. In humans, the disorder can be noted by ultrasound in utero to prepare for amputation after birth or complex bone lengthening surgery. The amputation usually takes place at six months with removal of portions of the legs to prepare them for prosthetic use. The other treatments which include repeated corrective osteotomies and leg-lengthening surgery (Ilizarov apparatus) are costly and associated with residual deformity.

The most prominent and extensively documented findings of Weismann-Netter-Stuhl syndrome are on plain radiographs of the bones. Findings include bilateral and symmetric anterior bowing of both tibiae and fibulae, lateral bowing of the tibiae, femoral bowing, and squaring of iliac and pelvis bones.

Weismann-Netter-Stuhl syndrome, also known as Weismann-Netter Syndrome or more technically by the term tibioperoneal diaphyseal toxopachyosteosis, is a rare disorder characterized by bowing of the lower legs and an abnormal thickening of thinner bone in the leg.

The main sign is anterior bowing and posterior cortical thickening of the diaphyses of both the tibiae and fibulae. It is thought to be inherited in an autosomal dominant fashion, and is most often bilateral and symmetric in nature. Associated features include dwarfism and mild intellectual disability, as well as a process known as tibialization of the fibulae, which involves thickening and enlargement of these bones to an extent resembling the tibiae. The combination of the presence of tibialization of the fibulae, which is highly specific for the disorder, and the absence of laboratory abnormalities ruling out alternative diagnoses including rickets, essentially confirms the diagnosis.

Proximal femoral focal deficiency (PFFD), also known as Congenital Femoral Deficiency (CFD), is a rare, non-hereditary birth defect that affects the pelvis, particularly the hip bone, and the proximal femur. The disorder may affect one side or both, with the hip being deformed and the leg shortened.

It is commonly linked with the absence or shortening of a leg bone (fibular hemimelia) and the absence of a kneecap. Other linked birth defects include the dislocation or instability of the joint between the femur and the kneecap, a shortened tibia or fibula, and foot deformities.

There are typically four classes (or "types") of PFFD, ranging from class A to class D, as detailed by Aitken.

Hemimelia comprises

- Fibular hemimelia, Congenital longitudinal deficiency of the fibula or Fibular longitudinal meromelia

- Tibial hemimelia, Congenital longitudenal deficiency of the tibia, Congenital aplasia and dysplasia of the tibia with intact fibula, Congenital longitudinal deficiency of the tibia or Tibial longitudinal meromelia

- Radial Hemimelia, Congenital longitudinal deficiency of the radius, Radial clubhand, Radial longitudinal meromelia or Radial ray agenesis

- Ulnar hemimelia, Congenital longitudinal deficiency of the ulna, Ulnar clubhand or Ulnar longitudinal meromelia

The cause of in-toeing can be differentiated based on the location of the disalignment. The variants are:

- Curved foot (metatarsus adductus)

- Twisted shin (tibial torsion)

- Twisted thighbone (femoral anteversion)

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.

Genu valgum, commonly called "knock-knee", is a condition in which the knees angle in and touch each other when the legs are straightened. Individuals with severe valgus deformities are typically unable to touch their feet together while simultaneously straightening the legs. The term originates from the Latin "genu", "knee", and "valgus" which actually means bent outwards, but in this case, it is used to describe the distal portion of the knee joint which bends outwards and thus the proximal portion seems to be bent inwards. For citation and more information on uses of the words Valgus and Varus, please visit the internal link to -varus.

Mild genu valgum is diagnosed when a person standing upright with the feet touching also shows the knees touching. It can be seen in children from ages 2 to 5, and is often corrected naturally as children grow. However, the condition may continue or worsen with age, particularly when it is the result of a disease, such as rickets or obesity. Idiopathic genu valgum is a form that is either congenital or has no known cause.

Other systemic conditions may be associated, such as Schnyder crystalline corneal dystrophy, an autosomal dominant condition frequently reported with hyperlipidemia.

The degree of genu valgum can be estimated by the , which is the angle formed by a line drawn from the anterior superior iliac spine through the center of the patella and a line drawn from the center of the patella to the center of the tibial tubercle. In women, the Q angle should be less than 22 degrees with the knee in extension and less than 9 degrees with the knee in 90 degrees of flexion. In men, the Q angle should be less than 18 degrees with the knee in extension and less than 8 degrees with the knee in 90 degrees of flexion. A typical Q angle is 12 degrees for men and 17 degrees for women.

The tibia or lower leg slightly or severely twists inward when walking or standing.

The diagnosis is based on the combination of unusual facial features and the dysplastic or absent femurs.

Diagnosis may be made antenatally.

Ectromelia is a congenital condition where long bones are missing or underdeveloped.

Examples include:

- Amelia

- Hemimelia

- Phocomelia

- Sirenomelia

Facial femoral syndrome is a rare congenital disorder. It is also known as femoral dysgenesis, bilateral femoral dysgenesis, bilateral-Robin anomaly and femoral hypoplasia-unusual facies syndrome. The main features of this disorder are underdeveloped thigh bones (femurs) and unusual facial features.

Raccoon eye/eyes (also known in the United Kingdom and Ireland as panda eyes) or periorbital ecchymosis is a sign of basal skull fracture or subgaleal hematoma, a craniotomy that ruptured the meninges, or (rarely) certain cancers. Bilateral hemorrhage occurs when damage at the time of a facial fracture tears the meninges and causes the venous sinuses to bleed into the arachnoid villi and the cranial sinuses. In layman's terms, blood from skull fracture seeps into the soft tissue around the eyes. Raccoon eyes may be accompanied by Battle's sign, an ecchymosis behind the ear. These signs may be the only sign of a skull fracture, as it may not show on an X-ray. They may not appear until up 2–3 days after the injury. It is recommended that the patient not blow their nose, cough vigorously, or strain to prevent further tearing of the meninges.

Raccoon eyes may be bilateral or unilateral. If bilateral, it is highly suggestive of basilar skull fracture, with a positive predictive value of 85%. They are most often associated with fractures of the anterior cranial fossa.

Raccoon eyes may also be a sign of disseminated neuroblastoma or of amyloidosis (multiple myeloma).

Depending on cause, raccoon eyes always require urgent consultation and management, that is surgical (facial fracture or post-craniotomy) or medical (neuroblastoma or amyloidosis).

More common cause: primary defect in endochondral ossification of the medial part of the femoral neck.

Excessive interuterine pressure on the developing fetal hip.

vascular insult.

Faulty maturation of the cartilage and metaphyseal bone of the femoral neck.

Clinical feature: presents after the child has started walking but before six years of age. Usually associated with a painless hip due to mild abductor weakness and mild limb length discrepancy.

If there is a bilateral involvement the child might have a waddling gait or trendelenburg gait with an increased lumbar lordosis. The greater trochanter is usually prominent on palpation and is more proximal. Restricted abduction and internal rotation.

X-ray: decreased neck shaft angle, increased cervicofemoral angle, vertical physis, shortened femoral neck decrease in femoral anteversion. HE angle (hilgenriener epiphyseal angle- angle subtended between a horizontal line connecting the triradiate cartilage and the epiphysisn normal angle is <30 degrees.

Treatment:

HE angle of 45–60 degrees observation and periodic follow up.

Indication for surgery :HE angle more than 60 degrees, progressive deformity, neckshaft angle <90 degrees, development of trendelenburg gait

Surgery: subtrochantric valgus osteotomy with adequate internal rotation of distal fragment to correct anteversion

common complication is recurrence. If HE angle is reduced to 38 degrees less evidence of recurrence

post operative spica cast is used for a period of 6–8 weeks.

Coxa vara is also seen in Niemann–Pick disease.

The sciatic nerve (; also called "ischiadic nerve", "ischiatic nerve", "butt nerve") is a large nerve in humans and other animals. It begins in the lower back and runs through the buttock and down the lower limb. It is the longest and widest single nerve in the human body, going from the top of the leg to the foot on the posterior aspect. The sciatic nerve provides the connection to the nervous system for nearly the whole of the skin of the leg, the muscles of the back of the thigh, and those of the leg and foot. It is derived from spinal nerves L4 to S3. It contains fibers from both the anterior and posterior divisions of the lumbosacral plexus.

Typical symptoms include pain, refusing to walk or bear weight and limping -bruising and deformity are absent. On clinical examination, there can be warmth and swelling over the fracture area, as well as pain on bending the foot upwards (dorsiflexion). The initial radiographical images may be inconspicuous (a faint oblique line) and often even completely normal. After 1–2 weeks however, callus formation develops. The condition can be mistaken for osteomyelitis, transient synovitis or even child abuse. Contrary to CAST fractures, non-accidental injury typically affect the upper two-thirds or midshaft of the tibia.

Other possible fractures in this area, occurring in the cuboid, calcaneus, and fibula, can be associated or can be mistaken for a toddler's fracture. In some cases, an internal oblique radiography and radionuclide imaging can add information to anterior-posterior and lateral views. However, since treatment can also be initiated in the absence of abnormalities, this appears to have little value in most cases. It could be useful in special cases such as children with fever, those without a clear trauma or those in which the diagnosis remains unclear. Recently, ultrasound has been suggested as a helpful diagnostic tool.

The groove begins on the lower and internal side of the base of the fifth toe, usually according to the plantar-digital fold. The groove becomes gradually deeper and more circular. The rate of spread is variable, and the disease may progress to a full circle in a few months, or still be incomplete after years. In about 75 per cent both feet are affected, though not usually to the same degree. There is no case reported where it begins in any other toe than the fifth, while there is occasionally a groove on the fourth or third toe. The distal part of the toe swells and appears like a small “potato”. The swelling is due to lymphatic edema distal to the constriction. After a time crusts can appear in the groove which can be infected with staphylococcus.

While the groove becomes deeper, compression of tendons, vessels and nerves occurs. Bone is absorbed by pressure, without any evidence of infection. After a certain time all structures distal the stricture are reduced to an avascular cord. The toe’s connection to the foot becomes increasingly slender, and if it is not amputated, it spontaneously drops off without any bleeding. Normally it takes about five years for an autoamputation to occur.

Cole describes four stages of ainhum:

Pain is present in about 78% of cases. Slight pain is present in the earliest stage of ainhum, caused by pressure on the underlying nerves. Fracture of the phalanx or chronic sepsis is accompanied with severe pain.

The Gosselin fracture is a V-shaped fracture of the distal tibia which extends into the ankle joint and fractures the tibial plafond into anterior and posterior fragments.

The fracture was described by Leon Athanese Gosselin, chief of surgery at the Hôpital de la Charité in Paris.

Some of the symptoms are:

- Pain and tingling in and around ankles and sometimes the toes

- Swelling of the feet

- Painful burning, tingling, or numb sensations in the lower legs. Pain worsens and spreads after standing for long periods; pain is worse with activity and is relieved by rest.

- Electric shock sensations

- Pain radiating up into the leg, and down into the arch, heel, and toes

- Hot and cold sensations in the feet

- A feeling as though the feet do not have enough padding

- Pain while operating automobiles

- Pain along the Posterior Tibial nerve path

- Burning sensation on the bottom of foot that radiates upward reaching the knee

- "Pins and needles"-type feeling and increased sensation on the feet

- A positive Tinel's sign

Tinel's sign is a tingling electric shock sensation that occurs when you tap over an affected nerve. The sensation usually travels into the foot but can also travel up the inner leg as well.

Symptoms typically include imbalance and visual problems. Dark or unsure situations generally increase this imbalance.The imbalance is worse in the dark or in situations where footing is uncertain. Spinning vertigo is unusual. Oscillopsia, visual symptoms of Bilateral Vestibulopathy only occur when the head is moving. For instance, when driving, a person with Bilateral Vestibulopathy may see very blurry objects. Oscillopsia is often common during walking. Transient visual blurring occurs with quick movements of the head.

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

Patients often complain of pain and swelling over the medial aspect of the knee joint. They may also report instability with side-to-side movement and during athletic performance that involves cutting or pivoting.