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Skeletal Survey Calculator 3
BETA TESTING
Home > Calculators > Skeletal Survey
Gestational age + measurements
Head circumference
Biparietal diameter
Optional: if you already have a TC percentile. Used only to raise/lower the tier (no numeric probability).
Tip: Use the thoracic lethality screen (TC/AC, FL/AC, and optional TC percentile) plus the pattern screens to generate a non-diagnostic, counseling-ready impression.
Pattern & Risk Screens (high-yield)
1) Viability / lethality screens
Use with TC/AC and rib findings.
2) Bone mineralization + fractures
3) Disproportion pattern (core classifier)
If present, specify bones below.
4) Shape-specific long bone features
5) Spine / pelvis clues
6) Craniofacial markers (beyond jaw index)
7) Associated anomalies
Morphology prompts (Head / Thorax / Hand / Foot)
Results
EMR-ready output
Note: Pattern-based statements are intentionally non-diagnostic and should be confirmed with imaging, genetics, and clinical context.
Design and JavaScript originally created 1/30/2020 by Mark Curran, MD, FACOG. Enhancements: mobile layout + pattern screens + consult-ready EMR text output (non-diagnostic) .

REFERENCES
Prenatally detected skeletal dysplasias - lethality quick table.- not exhaustive
Intended for rapid differential framing (not diagnostic). “Lethal” typically reflects death in the perinatal period due to severe pulmonary hypoplasia or extreme skeletal disease; exceptions occur.
Condition / group (commonly detected) Key prenatal ultrasound clues Thorax Lethality (typical) Common gene(s)
Thanatophoric dysplasia Severe micromelia; (Type 1 bowed “telephone receiver” femurs); macrocephaly; (Type 2 ± cloverleaf skull) Narrow thorax common Lethal FGFR3
Osteogenesis imperfecta type II / severe OI spectrum Decreased mineralization; fractures/callus; compressible skull; beaded ribs Small / hypoplastic Lethal COL1A1/COL1A2; others
Achondrogenesis spectrum Extreme micromelia; poor ossification; large head; hydrops common Very small Lethal COL2A1; SLC26A2; TRIP11; others
Hypophosphatasia (perinatal severe) Marked hypomineralization; short/bowed long bones; fractures may occur Small Lethal ALPL
Atelosteogenesis spectrum Severe limb shortening; abnormal bone shape; joint dislocations Often small Lethal FLNB; SLC26A2 (some)
Campomelic dysplasia Bowed long bones (esp. tibiae); hypoplastic scapulae; ambiguous genitalia; facial anomalies Often small Often lethal SOX9
Short-rib thoracic dysplasia / short-rib polydactyly groups Short ribs; very narrow thorax; polydactyly common; renal/cardiac anomalies possible Severely restricted Often lethal DYNC2H1, IFT140, WDR35, WDR60, IFT172, KIAA0586, TTC21B…
Jeune syndrome (asphyxiating thoracic dystrophy / ATD) Narrow thorax; short ribs; variable limb shortening; renal/liver disease may appear later Variable restriction Variable IFT140, DYNC2H1, WDR60, WDR34…
Jarcho-Levin / spondylocostal dysostosis spectrum Short trunk; segmentation anomalies; rib anomalies; scoliosis/kyphosis Variable Variable DLL3, TBX6, MESP2, LFNG, HES7…
Ellis-van Creveld Short limbs; postaxial polydactyly; congenital heart disease; short ribs may be mild Usually not lethal Usually survivable EVC, EVC2
Achondroplasia (heterozygous) Later-onset (21–27 w) rhizomelia; macrocephaly/frontal bossing; trident hand Usually adequate Usually survivable FGFR3
Achondroplasia (homozygous / severe phenotype variants) Earlier onset (15–16 w) rhizomelia; macrocephaly/frontal bossing; trident hand Severe chest narrowing Lethal FGFR3
Hypochondroplasia Milder rhizomelia; may be subtle prenatally Usually adequate Usually survivable FGFR3
Diastrophic dysplasia Short limbs; hitchhiker thumbs; clubfeet; joint contractures Usually adequate Usually survivable SLC26A2
Spondyloepiphyseal dysplasia congenita (SEDC) Short trunk; platyspondyly; mild limb shortening; possible micrognathia Variable Variable COL2A1
Kniest dysplasia Short trunk; abnormal epiphyses; limb shortening; facial findings Usually adequate Variable COL2A1
Chondrodysplasia punctata spectrum Epiphyseal stippling; limb shortening; cataracts/skin findings depending on type Variable Variable ARSE, EBP, PEX7…
Larsen syndrome spectrum Large-joint dislocations; clubfeet; characteristic facies; limb shortening variable Usually adequate Variable FLNB (classic)
Antley-Bixler spectrum Craniosynostosis; radiohumeral synostosis; femoral bowing; genital anomalies possible Variable Variable POR; FGFR2
Metatropic dysplasia Long-bone flaring; short trunk; progressive kyphoscoliosis Variable Variable TRPV4
Robinow syndrome Mesomelia; vertebral segmentation anomalies; genital anomalies; facial features Usually adequate Usually survivable ROR2, DVL1/3, WNT5A…
Osteopetrosis (severe infantile forms) Increased echogenicity/density (often subtle); fractures possible; macrocephaly Variable Variable TCIRG1; others
Schneckenbecken dysplasia Severe micromelia; characteristic pelvis; poor ossification Very small Lethal SLC35D1
Desbuquois dysplasia Type 1 Severe micromelia; joint laxity/dislocations; characteristic hand findings (extra ossification, delta phalanx, thumb bifidity) Narrow chest Often lethal CANT1
Desbuquois dysplasia Type 2 Short limbs; joint laxity/dislocations Usually adequate Variable XYLT1; sometimes CANT1
Opsismodysplasia Delayed ossification; short limbs; platyspondyly Variable Variable INPPL1
SHOX-related dysplasia spectrum (incl. LWD) Short long bones; mesomelia may be present; often subtle prenatally Usually adequate Usually survivable SHOX
Smith-McCort / Dyggve-Melchior-Clausen spectrum Short trunk; platyspondyly; delayed ossification Usually adequate Usually survivable RAB33B; DYM
Mucopolysaccharidosis (severe early forms) Hydrops; organomegaly; dysostosis features may be subtle prenatally Variable Variable Multiple
All calculations must be confirmed before use. The estimated results are not a substitute for clinical judgment. Neither perinatology.com nor any individual/organization involved in preparation/publication shall be liable for any damages resulting in whole or part from any use of or reliance upon results generated by this tool.
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UPDATED  01/02/2026
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