DMS 221 Chapter 65

Fetal Skeleton

shortening of proximal portion of bone

rhizomelia

slide 8

shortening of middle segment of bone

mesomelia

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abnormal shortening of limbs

micromelia

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partial or complete absence of bone in lower arm or leg

hemimelia

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short or absent limbs

phocomelia

sl 8

describes abnormal growth and density of cartilage and bone

skeletal dysplasia

sl 10

occurs secondary to skeletal dysplasia and refers to disproportionately short stature

dwarfism

sl 10

sonographic evaluation of skeletal dysplasias:

• assess limb ____

• assess bone ____

shortening; contour

sl 12

skeletal dysplasia suspected when limb lengths fall more than ____ standard deviations below mean

two

sl 12

most common lethal skeletal dysplasia

thanatophoric dysplasia

sl 16

thanatophoric comes from greek word ____

thanatos

sl 16

thanatos means

death personified

sl 16

thanatophoric dysplasia type I:

short, curved femurs and flat vertebral bodies

sl 118

thanatophoric dysplasia type II:

straight, short femurs, flat vertebral bodies, and cloverleaf skull

sl 18

sonographic features of ____:

• severe micromelia especially of proximal bones (rhizomelia)

• cloverleaf deformity

• narrow thorax with shortened ribs

thanatophoric dysplasia

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occurs as a result of premature craniosynostosis and may be associated with agenesis of corpus callosum

cloverleaf deformity

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other sonographic findings of ____:

• severe polyhydramnios

• hydrocephalus

• nonimmune hydrops

thanatophoric dysplasia

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most common non-lethal skeletal dysplasia

achondroplasia

sl 28

occurs in 2.53 of every 100,000 births

achondroplasia

sl 28

results from decreased endochondral bone formation

achondroplasia

sl 28

achondroplasia may not be evident until after __ weeks gestation

22

sl 28

produces short, squat bones (dwarfism)

achondroplasia

sl 28

most commonly results from spontaneous mutation

achondroplasia

sl 28

____ is a risk factor for achodroplasia

advanced maternal age

sl 28

____ achondroplasia, inherited from one parent:

• has good survival rate

• normal intelligence

• normal life span

heterozygous

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____ achondroplasia, inherited from two parents:

• considered lethal

homozygous

sl 31

sonographic findings of ____:

• rhizomelia

• macrocephaly

• trident hands (short proximal and middle phalanges)

• depressed nasal bridge

• frontal bossing

• mild ventriculomegaly may be identified

achondroplasia

sl 32

caused by cartilage abnormalities that result in abnormal bone formation and hypomineralization

achondrogenesis

sl 35

sonographic findings of ____:

• severe micromelia

• decreased or absent ossification of spine

• macrocephaly

• micrognathia

achondrogenesis

sl 38

rare disorder of collagen production leading to:

• brittle bones

• manifestations in teeth, skin, ligaments

• blue sclera

osteogenesis imperfecta

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mildest forms of osteogenesis imperfecta are types __ and __; unlikely that dx will be made in utero

I and IV

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osteogenesis imperfecta type __ is considered most severe form; lethal outcome

II

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children with types __ and __ may be short and multiple fractures during childhood

I and IV

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specific sonographic features of osteogenesis imperfecta type __ include:

generalized hypomineralization of bones, especially calvarium

multiple fractures of long bones, ribs, and spine

narrow thorax

micromelia

II

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in addition to findings, brain structures clearly visualized with osteogenesis imperfecta because of hypomineralization of ____

calvarium

slide 49

____ will be compressible with osteogenesis imperfecta

calvarium

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condition that presents with diffuse hypomineralization of bone caused by alkaline phosphatase deficiency

congenital hypophosphatasia

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dx of congenital hypophosphatasia is confirmed with ____ assay

alkaline phosphatase

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dx of congenital hypophosphatasia is confirmed with alkaline phosphatase assay, achieved through:

• fetal blood sampling

• chorionic villus sampling

• DNA analysis

slide 54

sonographic findings of ____:

• diffuse hypomineralization of bones

• moderate to severe micromelia

• extremities that may be bowed, fractured, or absent

• poorly ossified cranium with well-visualized brain structures

• small thoracic cavity

congenital hypophosphatasia

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very rare disorder characterized by:

• micromelia

• talipes

• cleft palate

• micrognathia

• scoliosis

• short stature

• earlobe deformities

• hand abnormalities

diastrophic dysplasia

slide 57

sonographic findings of ____:

• micromelia

• fixed abducted thumb (hitchhiker thumb)

diastrophic dysplasia

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camptomelic dysplasia is known as ____

bent bone

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____ is a group of lethal skeletal dysplasias characterized by bowing of long bones

camptomelic dysplasia

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sonographic findings of ____:

• bowing of long bones with lower extremities affected most severely

• small thorax

• hypoplastic fibulas

• hypoplastic scapulae

• hypertelorism

• cleft palate

• micrognathia

• talipes

• hydrocephalus

• polyhydramnios

• hydronephrosis

camptomelic dysplasia

slide 64

rare condition characterized by phocomelia and facial anomalies

roberts’ syndrome

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sonographic findings of ____:

• phocomelia, with upper extremeties more severely affected

• bilateral cleft lip and palate

• hypertelorism

• microcephaly

• cardiovascular, renal and gastrointestinal anomalies may be identified

roberts’ syndrome

slide 68

lethal skeletal dysplasia characterized by short ribs, short ribs, short limbs. and polydactyly

short-rib polydactyly syndrome

slide 70

sonographic findings of ____:

• narrow thorax with short ribs

• polydactyly

• micromelia

• midline facial cleft

short-rib polydactyly syndrome

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other sonographic findings of ____:

• anomalies of central nervous system

• anomalies of cardiovascular system

• anomalies of genitourinary system

short-rib polydactyly

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known as asphyxiating thoracic dysplasia

jeune’s syndrome

slide 75

skeletal dysplasia characterized by very narrow thorax

jeune’s syndrome

slide 75

sonographic findings of ____:

• small thorax

• rhizomelia

• renal dysplasia

• polydactyly (less common)

jeune’s syndromoe

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also known as chondroectodermal dysplasia

ellis-van creveld syndrome

slide 78

____ has an increased frequency in amish community estimated to be up to 1 in 5000 births

ellis-van creveld syndrome

slide 78

____ may present with:

• narrow thorax, causing pulmonary hypoplasia

• heart defects, the most common of which is atrial septal defect (ASD)

ellis-van creveld syndrome

slide 79

other features identified with ellis-van creveld syndrome include:

• abnormal teeth

• hypoplastic nails

• thin hair

slide 80

sonographic findings of ____:

• limb shortening

• narrow thorax

• polydactyly

• heart defects (50%)

ellis-van creveld syndrome

slide 81

anomaly in which there is fusion of lower extremities

sirenomelia

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sonographic findings of ____:

• sacral agenesis

• talipes

• abnormal lumbar vertebrae, pelvic abnormalities, contractures, or decreased movement of lower extremeties

caudal regression syndrome/ sirenomelia

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sonographic findings of ____:

• variable fusion of lower extremities

• bilateral renal agenesis

• oligohydramnios

• single umbilical artery

sirenomelia

slide 87

group of anomalies that may occur together

VACTERL

slide 90

VACTERL anomalies:

• vertebral defects

• anal atresia

• cardiac anomalies

• tracheoesophageal fistula

• renal anomalies

• limb dysplasia

slide 90

when VACTERL association seen with accompanying ____, condition is termed VACTERL - H syndrome

hydrocephalus

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multiple events can cause decrease in fetal movement:

• oligohydramnios

• multiple gestations

• congenital uterine anomalies

slide 93

sonographic findings of ____:

• rigid extremities

• flexed arms

• hyperextension of knees

• clenched hands

• talipes

arthrogryposis multiplex congenita

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____ is characterized by:

• abnormal joint contractures

• facial abnormalities

• polyhydramnios

• IUGR

• pulmonary hypoplasia

pena-shokeir syndrome

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____ and trisomy 18 have similar features, so karyotyping should be offered

pena-shokeir syndrome

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sonographic findings of ____:

• limb abnormalities (contractures, clinched hands, talipes, rocker-bottom feet)

• facial abnormalities (micrognathia and cleft palate)

• polyhydramnios and hydrops may be identified

pena-shokeir syndrome

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amputation defects may be identified as total or partial absence and may be associated with ____

amniotic band syndrome

slide 103

also known as talipes

clubfoot

slide 111

describes deformities of foot and ankle.

clubfoot/talipes

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persistent abnormal inversion of the foot perpendicular to the lower leg

clubfoot/talipes

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majority of clubfoot cases are ____

idiopathic

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characterized by prominent heel and convex sole

rocker-bottom foot

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the dietary supplement ____ has been shown to significantly reduce the likelihood of a fetus suffering from neural tube defects

folate

slide 115

scan planes used to evaluate the fetal spine

sag, trv, coronal

slide 115

there should be __ ossification centers for each vertebra

3

slide 115

term used to describe the absence of all or part of a vertebral body

hemivertebra

slide 116