Diagnostic ultrasound ( PDFDrive )

CHAPTER 40 The Fetal Musculoskeletal System 1397
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A
B
C
D E F
FIG. 40.23 Polydactyly. (A) Ellis–van Creveld syndrome. Postaxial polydactyly on cross section through six digits. (B) Corresponding
radiograph shows postaxial polydactyly. Note hypoplastic distal phalanges and fusion of the third and fourth metacarpals. (C) Corresponding
pathology specimen. (D) Polydactyly may present as a soft tissue nubbin with no bony elements. (E) Ellis–van Creveld with toe polydactyly. (F)
Three-dimensional ultrasound image shows isolated familial polydactyly.
TABLE 40.6 Rhizomelic Dysplasia: Key Features
Dysplasia Prognosis Degree of Limb Shortening Key Sonographic Features
Heterozygous achondroplasia Nonlethal Mild Progressive discrepancy in femur length and
biparietal diameter
Chondrodysplasia punctata, Lethal Moderate-severe Stippled epiphysis in third trimester
rhizomelic form
Diastrophic dysplasia Variably lethal Mild-moderate Hitchhiker thumb, postural deformities,
dislocations, joint contractures, clubfoot
TABLE 40.7 Micromelic Dysplasia, Mild: Key Features
Dysplasia Prognosis Key Sonographic Features
Asphyxiating thoracic May be lethal Long narrow thorax, renal anomalies (cystic dysplasia), polydactyly (14%)
dystrophy
Ellis–van Creveld syndrome May be lethal Long narrow thorax, congenital heart disease (50% atrial septal defect),
polydactyly (100%)
TABLE 40.8 Micromelic Dysplasia, Mild and Bowed: Key Features
Dysplasia Prognosis Key Sonographic Features
Osteogenesis imperfecta
type III
Nonlethal, progressively
deforming
Lower extremities demonstrate greater degree of shortening and
fractures/bowing
Campomelic dysplasia Variably lethal Ventral-bowing femur and tibia, hypoplastic or absent ibula,
hypoplastic scapulas