fetal musculoskeletal pt1

Question 1

When can most of the fetal bones be imaged?

Answer 1

15-16 wks

Question 2

What is the name for the arms and legs (including long bones)?

Answer 2

Appendicular skeleton
(extremely long bones, metacarpals, metatarsals, phalanges can all be seen and are well ossified by 2nd trimester)

Question 3

What bones are not ossified until after birth and therefore cannot be seen?

Answer 3

carpals

(exception, is calcaneus which ossifies by 5th and 6th month)important in seeing Club Foot deformity

Question 4

The scapulae and clavicles can be seen. What does the clavicular length roughly correlate with?

Answer 4

gestational age of fetus

Question 5

Name the upper extremity bones?

Answer 5

humerus, radius (thumb side), ulna(pinky side)

Question 6

Name the lower extremity bones?

Answer 6

femur (measured as part of 4 biometrics), tibia (medial and larger), fibula (could remove to lose weight :)

Question 7

What is the name for the cranium, face, spine, and pelvis?

Answer 7

axial skeleton

Question 8

What are the facial bones?

Answer 8

orbits, maxilla (upper jaw), mandible (lower jaw), osseous nasal septum

Question 9

When can the iliac ossification centers be seen? What about the ischial ossification centers?

Answer 9

early second trimester, about 20 weeks

Question 10

What are the two classification methods that exist for skeletal disorders?

Answer 10

one accounts for gene and protein defects, the other is based upon embryonic pattern of limb abnormalities

Question 11

Can environmental factors alter embryologic differentiation causing limb malformations?

Answer 11

Yes, exposure to drugs, hormones, viral infections, radiation, and hyperglycemia in the mother

Question 12

What are the 3 distinct characteristics of lethal dysplasias?

Answer 12

Severe micromelia, severely hypoplastic thorax, and the identification of a Specific Feature of the lethal dysplasia.

Question 13

When a long bone measures more than 4 standard deviations below the mean? FL/AC less than .16 helps define the degree of shortness as severe.

Answer 13

Severe micromelia

Question 14

When the thorax is severely hyperplastic, the lungs can’t develop? (no survival) Thoracic circumference less than the 5th percentile for gestational age.

Answer 14

Severely hypoplastic thorax

Question 15

What is an example of a Specific Feature of lethal dysplasia?

Answer 15

multiple fractures in utero indicate osteogenesis imperfecta type II (lethal form)

Question 16

Most common lethal dysplasia? Three leaf clover skull.

Answer 16

Thanatophoric dysplasia

Question 17

A rare lethal form of short limbed dyplasia with a lack of vertebral ossification-(KEY)?

Answer 17

AchondroGenesis

Question 18

Which type of AchondroGenesis is more severe? (20% of all cases)

Answer 18

Type 1

Question 19

Which type of AchondroGensis is less severe and autosomal dominant? (80% of all cases)

Answer 19

Type 2

Question 20

What type of Osteogenesis imperfecta is the lethal form?

Answer 20

Type 2 is lethal

Question 21

Lethal dysplasia with Abnormally fragile bones, fractures in utero, bones look really thick, disorder of production of collagen

Answer 21

Osteogenesis imperfecta type II

Question 22

Lethal dysplasia with Rare bone demineralization-(KEY) disorder due to low levels of serum and tissue alkaline phosphatase

Answer 22

Congenital hypophosphatasia

Question 23

Lethal dysplasia with bent/bowed bones (most commonly tibia and femur) sometimes referred to as “telephone receiver” deformities

Answer 23

Camptimelic dysplasia

Question 24

Lethal short limb dysplasia characterized by rhizomelia dwarfism

Answer 24

Homozygous dominant achondroplastic dwarfism

Question 25

Lethyl dysplasia characterized by polydactyly (many digits)

Answer 25

Short rib polydactyly syndrome

Question 26

In all of these lethal syndromes they are similar in that they all have what?

Answer 26

short extremities, and small thoracies (BUT there is one particular feature in each to guide us to which disease it is)

Question 27

LETHAL DYSPLASIA

1. ) Thanatophoric dysplasia/dwarfism
2. ) AchondroGenesis
3. )Osteogenesis imperfecta type II
4. )Congenital hypophosphatasia
5. )Camptimelic dysplasia
6. )Homozygous dominant achondroplastic dwarfism
7. )Short rib polydactyly syndrome

Answer 27

THE ONE DEFINING FEATURE

1. ) most common/ 3 leaf clover skull (Kleeblattshcadel)
2. ) lack of vertebral ossification
3. ) fractures in utero/bones look thick
4. ) bone demineralization
5. )bent/bowed bones/ telephone receiver
6. ) rhizomelia dwarfism
7. ) polydactyly (many digits)