Chapter 12 Flashcards
Radiologists use the appearance of various ossification centers to determine whether a child has reached his or her proper maturation age
Bone age
obtained from ossification studies in the hands and wrists of children
Bone age
Abnormalities of the limbs vary greatly, and they may be represented by partial [___] or complete absence [___] of one or more of the extremities
meromelia - Amelia
Sometimes, the long bones are absent, and rudimentary hands and feet are attached to the trunk by small, irregularly shaped bones [____, a form of meromelia]
phocomelia
Sometimes, all segments of the extremities are present but abnormally short [____]
micromelia
Many mothers of these infants had taken ___, a drug widely used as a sleeping pill and antinauseant.
thalidomide
Sometimes, the digits are shortened [___]
brachydactyly
If two or more fingers or toes are fused, it is called ___
syndactyly
The presence of extra fingers or toes is called ___. The extra digits frequently lack proper muscle connections
polydactyly
Abnormalities involving polydactyly are usually bilateral, whereas absence of a digit [___], such as a thumb, usually occurs unilaterally
ectrodactyly
____ consists of an abnormal cleft between the second and fourth metacarpal bones and soft tissues
Cleft hand and foot
The role of the HOX genes in limb development is illustrated by two abnormal phenotypes produced by mutations in this family of genes: Mutations in ___ result in hand-foot genital syndrome, characterized by fusion of the carpal bones and small short digits
HOXA13
The role of the HOX genes in limb development is illustrated by two abnormal phenotypes produced by mutations in this family of genes: Mutations in HOXA13 result in____, characterized by fusion of the carpal bones and small short digits
hand-foot genital syndrome
Mutations in ___ result in a combination of syndactyly and polydactyly [synpolydactyly]
HOXD13
Mutations in HOXD13 result in a combination of syndactyly and polydactyly [___]
synpolydactyly
__ mutations [chromosome 12q24.1] result in Holt-Dram syndrome, characterized by upper limb abnormalities and heart defects consistent with a role for this gene in upper limb and heart development
TBX5
TBX5 mutations [chromosome 12q24.1] result in ___, characterized by upper limb abnormalities and heart defects consistent with a role for this gene in upper limb and heart development
Holt-Dram syndrome
___ is characterized by shortening, bowing, and hypomineralization of the long bones of the limbs that can result in fractures and blue sclera
Osteogenesis imperfecta
In most cases, dominant mutations in the __ or __ genes involved in production of type I collagen cause the abnormalities
COL1A1 or COL1A2
In most cases, dominant mutations in the COL1A1 or COL1A2 genes that are involved in production of ___ cause the abnormalities
type I collagen
___ is caused by mutations in the FIBRILLIN [FBN1] gene located on chromosome 15q21.1
Marfan syndrome
Marfan syndrome is caused by mutations in the ___ gene located on chromosome 15q21.1
FIBRILLIN [FBN1]
___ may be caused by arthrogryposis but is more commonly considered to be idiopathic in origin
Clubfoot
___ usually involves more than one joint and may be caused by neurological defects [motor horn cell deficiency, meningomyelocele], muscular abnormalities [myopathies, muscle agenesis], and joint and contiguous tissue problems [synostosis, abnormal development]
Arthrogryposis [congenital joint contractures]
___ is usually a genetic abnormality observed with malformations in other structures, such as craniosynostosis-radial aplasia syndrome [Baller—Gerold syndrome]
Congenital absence or deficiency of the radius
Congenital absence or deficiency of the radius is usually a genetic abnormality observed with malformations in other structures, such as ___ [Baller—Gerold syndrome]
craniosynostosis-radial aplasia syndrome
___ may cause ring constrictions and amputations of the limbs or digits
Amniotic bands
___ are limb defects in which proximal structures are intact, but structures distal to a transverse plane are partially or completely absent
Transverse limb deficiencies
___ consists of underdevelopment of the acetabulum and head of the femur
Congenital hip dislocation
