The Fetal Skeleton Flashcards
Aplasia
Absence of bone
Hypoplasia
Incomplete development
Amelia
Absence of one or more limbs
Hemimelia
Absence of one or more extremities below the elbow or knee
Acheiria
Absence of one or more hands
Apodia
Absence of one or more feet
Adactyly
Absence of one or more digits from the hands of feet
Phocomelia
Absence of the proximal portion of an extremity with the hand or foot attached to the trunk
Meromelia
Absence of part of a limb
Aplasia or hypoplasia of what bone is common in many skeletal syndrome?
Radius
What abnormality can be described as a linear density attached from the uterine wall?
ABS
What abnormality is known as mermaid syndrome?
Sirenomelia
Prognosis for sirenomelia is usually poor due to?
Renal agenesis
What is known as a rare form of short limbed dwarfism?
Camptomelic dysplasia
What is an inherited rare disease of defective bone mineralization?
Congenital hypophosphatasia
Apert syndrome is a type of what?
Craniofacial dysotosis
In what abnormality is trident hand seen in?
Achondroplasia
A persistently clenched hand with an overlapping index finger is strongly associated with?
Trisomy 18
Pre-axial polydactyly affects?
Radial side
Post-axial polydactyly affects?
Ulnar side
Achondroplasia sonographic features:
Ready
For
Little
Tiny
Men
Rhizomelic limbs
Frontal bossing
Low nasal bridge
Trident hand
Macrocephaly/hydrocephaly
How early can limb buds be visualized?
8 weeks
When do the bones in hands and feet form?
11-13 weeks
When can fetal long bones be accurately measured?
12 weeks
Femoral length varies according to what factors?
- Maternal weight
- Ethnicity
- Height
T or F? The fetal femur grows 2mm per week in the third trimester?
FALSE: It grows 3mm per week from 14-27 weeks and 1mm per week in the third trimester
Features of bones in skeletal dysplasia?
- Shortened
- Thinned
- Deformed
What abnormality is associated with craniosynostosis/ or cloverleaf deformity?
Thanatophoric Dysplasia
Lethal skeletal dysplasias are often accompanied by?
Pulmonary hypoplasia
What type of TD is most common?
Type I
In what abnormality do the limbs have a “telephone receiver appearance”?
TD - Type I
What is the most common form of lethal skeletal dysplasia?
TD
What abnormality is seen with platyspondyly?
Type I TD
Most common skeletal dysplasia to result in stillbirth?
TD
What abnormality is seen with a “champagne cork appearance” of a narrow thorax with protruding abdomen?
TD
Two types of Achondrogenesis?
Type I - Parenti Fraccaro
Type II - Langer Saldino
OI may present with what three things:
Long bone and rib fractures
Blue sclera
Hearing impairment
What type of OI is caused by an abnormal decrease in collagen?
Type I
When do most rib fractures occur in Type I osteogenesis imperfecta?
After birth
What is the most mild and most severe form of OI?
Type II - most severe
Type IV - most mild
In what type of OI do infants die shortly after birth?
Type II
In what abnormality may you see a bell-shaped appearance of the thorax?
Type II OI and Camptomelic Dysplasia
What type of OI do you see limb bowing in utero?
Type III
What type of OI is not detected in utero?
Type IV
Characteristics of Camptomelic Dysplasia:
Short bowed limbs
Short trunk
Large head
Bell-shaped chest
Hypoplastic scapule
In what abnormality might the skull be easily compressed and spurs are seen in the middle of long bones?
Congenital hypophosphatasia
What type of congenital hypophosphatasia is detected in utero?
Type I - decreased ossification with short, bent bones
What abnormality is known as abnormal ossification?
Dysostosis
What abnormality is associated with widening of the cranial fontanelles?
Cleidocranial dysostosis
What abnormality is associated with absent or hypoplastic clavicles?
Cleidocranial dysostosis
“Mitten hand” is seen in what abnormality?
Apert syndrome
When can the fetal hands be best visualized? (trimester)
Late first or mid-second
Has poly or oligo been reported in fetuses with VACTERL?
Polyhydramnios
Clubfoot is most commonly due to?
Oligohydramnios
In what abnormality will you see an overall reduction in ossification with short-bent bones?
Congenital hypophosphatagia
T or F? Type 2 congenital hypophosphatasia is lethal
False: Type 1 is detected in utero and is lethal
What abnormalities can VACTERL Association possibly simulate? (3)
Trisomy 13
Trisomy 18
Sirenomelia