Chapter 65 Fetal Skeleton Flashcards
term used to describe abnormal growth and density of bones and cartilage
Skeletal dysplasia
- refers to disproportionately short stature
- occurs secondary to skeletal dysplasia
dwarfism
dysplasia is suspected when limb lengths fall more than ____ standard deviations below the mean
2
when skeletal dysplasia is suspected, the protocol should be adjusted to include:
- Asses limb shortening
- Assess bone contour
- Estimate degree of ossification
- Evaluate thoracic circumference and shape
- survey for coexistent hand and foot anomalies
- evaluate face & profile
- Survey for other anomalies
when assesing the bone contour, you should note:
-fractures, thickness, abnormal bowing, ribbon-like appearance, curvature
decreased attenuation of bones with decreased shadowing suggest _________
hypomineralization
when evaluating the face & profile, be especially aware of:
facial clefts
shortening of the humerus/femur(proximal segment)
rhizomelia
shortening of the radius/ulna or tib/fib(middle)
mesomelia
shortening of the proximal & middle segments
micromelia
most common lethal skeletal dysplasia:
thanatophoric dysplasia
subdivision of thanatophoric dysplasia that has short CURVED femurs and flat vertebral bodies.
Type 1
subdivision of thanatophoric dysplasia that has short STRAIGHT femurs, flat vertebral bodies, and cloverleaf skull
Type 2
Infants with thanatophoric dysplasia die shortly after birth due to:
pulmonary hypoplasia from the narrow thorax
sonographically, thanatophoric dysplasia will have:
severve micromelia(especially proximal bones
- clover-leaf skull
- frontal bossing
- narrowed thorax and shortened ribs
most common non-lethal skeletal dysplasia
achondroplasia
_____ increases the risk of achondroplasia
advanced paternal age
lethal form of achondroplasia
homozygous achondroplasia
most common cause of achondroplasia
spontaneous mutation
form of achondroplasia inherited from 1 parent, normal intelligence and life span
heterozygous achondroplasia
sonographic findings of achondroplasia:
- rhizomelia
- macrocephally
- trident hands
caused by cartilage abnormalities which result in abnormal bone formation & hypomineralization
achondrogenesis
type 1 achondrogenesis:
- more severe
- autosomal-recessive
type 2 achondrogenesis:
- less severe
- more common
- results from spontaneous mutation
patients with achondrogenesis are either stillborn or die shortly after birth due to _____
pulmonary hypoplasia
sonographic findings of achondrogenesis:
- severe micromelia
- macrocephaly
- micrognathia
- decreased/absent ossification of spine
disorder of collagen production leading to brittle-bones
Osteogenesis Imperfecta
blue sclera(blue tint to the whites of the eyes) occurs with
osteogenesis imperfecta
osteogenesis imperfecta classifications: _____ & ______ are the mildest forms
types 1 and 4
osteogenesis imperfecta classifications: severe form, transmited autosomal-dominant/recessive manner
type 3
osteogenesis imperfecta classifications: most severe form, lethal. Inherited autosomal dominant/recessive, or spontaneous mutation
type 2
sonographic findings of osteogenesis imperfecta:
- increased NT in 1st trimester
- hypomineralization, especially of the skull
- multiple fractures
- compressible skull bones
Diffuse hypomineralization of bone caused by an alkaline phosphatase deficiency
congenital hypophosphatasia
diagnosis of congenital hypophosphatasia is achieved through:
- fetal blood sampling
- Chorionic Vili sampling(CVS)
- DNA analysis
sonographic findings of congenital hypophosphatasia:
- diffuse hypomineralization
- poorly ossified cranium with well visualized brain structures
rare, characterized by micromelia, fixed abducted thumb(Hitch-hikers thumb), micrognathia
Diastropic Dysplasia
Characterized by bowing of the long bones
Camptomelic Dysplasia
Camptomelic dysplasia is also known as _________
Bent Bone Dysplasia
infants with camptomelic dysplasia usually die in the neonatal period due to
pulmonary hypoplasia
sonographic findings of camptomelic dysplasia
bowing of long bones(especially the lower extremities)
characterized by:
- absent segment of an extremity
- hands & feet are attached to body like a flipper
Roberts syndrome
Roberts syndrome is also known as
pseudothalidomide syndrome
sonographic findings of roberts syndrome
phocomelia(absent segment of extremity) with the upper extremities more severely affected
Characterized by:
- short ribs
- extra fingers(polydactyl)
- short limbs
Short-Rib Polydactyl syndrome
characterized by small/narrow thorax, renal dysplasia, rhizomelia
Jeune’s syndrome
Jeune’s syndrome is also known as
asphyxiating thoracic dysplasia
Increased frequency amoung amish community, presents with narrow thorax, heart defects, limb shortening, abnormal teeth, thin hair, hypoplastic nails
Ellis-Van Creveld Syndrome
Ellis-Van Creveld syndrome is also known as
Chondroectodermal dysplasia
most common heart defect with Ellis-Van Creveld syndrome:
atrial septal defect
Range of malformations of the caudal end of the neural tube
Caudal Regression syndrome
Caudal Regression syndrome is linked to _____
maternal diabetes
Sonographic findings of caudal regression syndrome:
- absent sacrum and coccyx
- decreased movement of lower extremities
- abnormal lumbar vertebrae
Fusion of the lower extremities
Sirenomelia
Sirenomelia is also known as:
mermaid syndrome
Sirenomelia is more common in:
males
Sirenomelia is lethal due to:
-bilateral renal agenisis
sirenomelia is associated with:
- diabetes
- cocaine use
- monozygotic twinning
sonographic findings of sirenomelia
- bilateral renal agenesis
- fusion of lower extremities
- single umbilical artery
VACTERL anomalies are:
Vertebral Anal atresia Cardiac TracheoEsophageal fistula Renal Limb dysplasia
For VACTERL to be considered ________ features must be present
3 out of 5
VACTERL-H is when VACTERL is seen with _____
hydrocephalus
Severe contractures(hardening & shortening of muscles, tendons, or other tissue) of extremities
Athrogryposis Multiplex Congenita
Sonographic findings of Athrogryposis Multiplex Congenita
- rigid extremities
- hyperextension of knees
Athrogryposis Multiplex Congenita is due to:
- abnormal innervation
- disorders of muscles & connective tissue
amputation defects may be seen in association to:
amniotic band syndrome
congenital absence of 1 or all extremities
amelia
fused digits
syndactyly
overlapping digits
clinodactyly
split hand/lobster claw deformity:
ectrodactyly
abnormal inversion of the foot perpendicular to the lower leg
clubfoot
rockerbottom foot is especially associated with
Trisomy 18
hypoplasia or aplasia of the radius and thumb
Radial ray defects
radial ray defects are associated with these chromosomal abnormalities:
- Trisomy 13 & 18
- VACTERL
radial ray defects are associated with these syndromes:
- Holt-Oram syndrome
- TAR(thrombocytopenia with Absect Radi syndrome)
