Birth defects of the face and limbs are fairly common. They may involve only a specific body part, such as the mouth (cleft lip Cleft Lip and Cleft Palate The most common birth defects of the skull and face are cleft lip and cleft palate, affecting about 2 of every 1,000 babies. Cleft lip is a separation of the upper lip, usually just below the... read more 
or cleft palate Cleft Lip and Cleft Palate The most common birth defects of the skull and face are cleft lip and cleft palate, affecting about 2 of every 1,000 babies. Cleft lip is a separation of the upper lip, usually just below the... read more ) or foot (clubfoot Clubfoot and Other Foot Defects Clubfoot (talipes equinovarus) is a birth defect in which the foot and ankle are twisted out of shape or position. The usual clubfoot is a down and inward turning of the hind foot and ankle... read more 
). Or they may be part of a genetic syndrome of many abnormalities, such as Treacher Collins syndrome, in which birth defects affect not only the face but also multiple other body parts.
Birth defects may be classified as
Deformities
Malformations
A deformity is a change in the shape of a body part. A deformity is caused by unusual pressure on the baby in the womb (for example, some forms of clubfoot) or after the baby is born (for example, some deformities of the skull Craniosynostosis Craniosynostosis is a birth defect in which one or more of the skull's sutures close too early. (See also Introduction to Birth Defects of the Face, Bones, Joints, and Muscles.) The sutures... read more 
). Deformities are present in about 2% of births. Some deformities improve without treatment within a few days, but others need to be treated.
A malformation is an error in the baby's development that occurs in the womb. Causes of malformations include chromosome abnormalities Overview of Chromosome and Gene Disorders Chromosomes are structures within cells that contain a person's genes. A gene is a segment of deoxyribonucleic acid (DNA) and contains the code for a specific protein that functions in one or... read more , single-gene defects Inheritance of Single-Gene Disorders Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are made of a very long strand... read more , and environmental factors (such as teratogens Exposures During Pregnancy Some risk factors are present before women become pregnant. These risk factors include Certain physical characteristics, such as age, and social characteristics of women Problems in a previous... read more 
, which are substances known to cause birth defects). A malformation can also be caused by a combination of genetic and environmental factors. In some cases, the cause is unknown. About 3 to 5% of babies are born with a malformation.
Arthrogryposis multiplex congenita Arthrogryposis Multiplex Congenita Arthrogryposis multiplex congenita refers to a variety of conditions that involve limited joint movement. Any condition that impairs the movement of the baby while in the womb can result in... read more 
refers to a variety of joint and muscle problems that result from limited joint movement in the womb.
Craniofacial defects are caused by the abnormal growth or development of the head and/or facial bones while the baby is growing inside the mother. The most common defects of the face are cleft lip and cleft palate Cleft Lip and Cleft Palate The most common birth defects of the skull and face are cleft lip and cleft palate, affecting about 2 of every 1,000 babies. Cleft lip is a separation of the upper lip, usually just below the... read more . Other defects may involve the ears Ear Defects Ears can be missing, deformed, or incompletely developed at birth. (See also Introduction to Birth Defects of the Face, Bones, Joints, and Muscles.) Birth defects of the ear include the following... read more 
, eyes Eye Defects Eyes can be missing, deformed, or incompletely developed at birth. Birth defects of the eye include the following: Hypertelorism: Widely spaced eyes, can occur in several congenital syndromes... read more 
, and jaw Jaw Defects The jaw can be missing, deformed, or incompletely developed at birth. Birth defects of the jaw include Micrognathia Agnathia Maxillary hypoplasia read more . Some craniofacial defects that affect the skull include macrocephaly Macrocephaly Macrocephaly is the technical term for a large head. Macrocephaly can be normal or caused by genetic disorders or other disorders. Diagnosis is made before birth through routine ultrasound tests... read more (the skull is too large), microcephaly Microcephaly Microcephaly is an abnormally small head. Often the head is small because the brain is small and abnormally developed. Microcephaly can be caused by many disorders including genetic abnormalities... read more 
(the skull is too small), and craniosynostosis Craniosynostosis Craniosynostosis is a birth defect in which one or more of the skull's sutures close too early. (See also Introduction to Birth Defects of the Face, Bones, Joints, and Muscles.) The sutures... read more (the bands of tissue that connect the bones of the skull close too early).
Hip and joint defects include developmental dysplasia of the hip Developmental Dysplasia of the Hip Developmental dysplasia of the hip is a birth defect in which the bones in the hip may be incorrectly developed. In developmental dysplasia of the hip, formerly called congenital dislocation... read more and knee dislocation Dislocated Knee The knee may be dislocated at birth. Although rare, a dislocated knee in a newborn may be related to the position in the womb before birth. This defect can also occur in children who have Larsen... read more .
Limb defects Missing or Incompletely Formed Limbs Limbs can be missing, deformed, or incompletely developed at birth. Limbs may form abnormally. For example, bones in the hand and forearm may be missing because of a genetic defect (see Chromosome... read more 
are numerous. Sometimes a limb is missing or does not form completely Missing or Incompletely Formed Limbs Limbs can be missing, deformed, or incompletely developed at birth. Limbs may form abnormally. For example, bones in the hand and forearm may be missing because of a genetic defect (see Chromosome... read more . Part or all of the hand or foot may be missing. For example, the person may have too few or too many fingers or toes. Clubfoot Clubfoot and Other Foot Defects Clubfoot (talipes equinovarus) is a birth defect in which the foot and ankle are twisted out of shape or position. The usual clubfoot is a down and inward turning of the hind foot and ankle... read more (talipes equinovarus) is a defect in which the foot and ankle are twisted out of shape or position. Other foot defects include metatarsus adductus Metatarsus adductus Clubfoot (talipes equinovarus) is a birth defect in which the foot and ankle are twisted out of shape or position. The usual clubfoot is a down and inward turning of the hind foot and ankle... read more , metatarsus varus Metatarsus varus Clubfoot (talipes equinovarus) is a birth defect in which the foot and ankle are twisted out of shape or position. The usual clubfoot is a down and inward turning of the hind foot and ankle... read more , talipes calcaneovalgus Talipes calcaneovalgus Clubfoot (talipes equinovarus) is a birth defect in which the foot and ankle are twisted out of shape or position. The usual clubfoot is a down and inward turning of the hind foot and ankle... read more , and pes planus Pes planus (flat feet) Clubfoot (talipes equinovarus) is a birth defect in which the foot and ankle are twisted out of shape or position. The usual clubfoot is a down and inward turning of the hind foot and ankle... read more .
In bowlegs, Bowlegs In bowlegs, what doctors call genu varum, the legs appear curved out at the knees so that the knees are more widely separated than normal. This appearance is usually created by the position... read more 
the knees appear to be turned outward. In knock-knees, Knock-knees In bowlegs, what doctors call genu varum, the legs appear curved out at the knees so that the knees are more widely separated than normal. This appearance is usually created by the position... read more the knees appear to be turned inward. Other defects that affect the legs include twisting of the top part of the thighbone (femoral torsion Femoral Torsion The thighbone (femur) may be twisted at birth. The femoral head is the top part of the thighbone (femur), the largest bone in the leg. The femoral head may be twisted (called torsion) either... read more ) and twisting of the shinbone (tibial torsion Tibial Torsion The shinbone (tibia) may be twisted at birth. The shinbone (tibia) is one of the bones in the lower leg. Twisting (called torsion) of the tibia toward the outside (external torsion) occurs normally... read more ).
Muscle defects Muscle Defects Babies can be born missing individual muscles or groups of muscles, or muscles can be incompletely developed. Birth defects of the muscles can occur alone or as part of a syndrome. The pectoralis... read more 
may be present at birth. Babies can be born missing individual muscles or groups of muscles, or muscles can be incompletely developed. Defects in muscles can occur alone or as part of a syndrome.
Neck and back abnormalities can be caused by injuries to soft tissues or bones. Two of the most common abnormalities are
Spinal defects include scoliosis Scoliosis Scoliosis is abnormal curvature of the spine. Scoliosis can be present at birth or can develop during adolescence. Mild forms may cause only mild discomfort, but more severe forms can cause... read more 
, which is rarely apparent at birth, and defects of a specific vertebra, which are likely to be identified at birth. A number of different genetic syndromes include scoliosis as one of their abnormalities. As children grow, the spinal curve caused by a defect of the spine can progress quickly. Doctors monitor the spine closely. The child may need to wear a brace or body jacket for up to 18 hours a day. Surgery may be needed.
