Ch. 16 Fetal Musculoskeletal System

Question 1

By what gestational age can most bones be imaged?

Answer 1

15-16 weeks

Question 2

Which bone is longer, the radius or ulna?

Answer 2

The ulna is on the pinky side and it is longer than the radius which is on the thumb side

Question 3

Which bone is larger, the tibia or the fibula?

Answer 3

The tibia is located medially and it is larger than the fibula which is thinner and located laterally.

Question 4

What bones make up the axial skeleton?

Answer 4

Cranium, facial bones, pelvis and spine

Question 5

Shortening of the proximal segment of an extremity (ie Humerus and femur)

Answer 5

Rhizomelia

Question 6

Shortening of the middle segment of an extremity (ie rad/ulna and tib/fib)

Answer 6

Mesomelia

Question 7

Shortening of the distal segment of an extremity (ie hand or foot)

Answer 7

Acromelia

Question 8

Term for shortened extremities

Answer 8

micromelia

Question 9

term for an absent segment of an ext

Answer 9

phocomelia

Question 10

Term for the complete absence of an entire ext

Answer 10

Amelia

Question 11

Presence of more than five digits

Answer 11

Polydactyly

Question 12

Soft tissue or bony fusion of the digits

Answer 12

Syndactyly

Question 13

Term for when a long bone measures more than 4 SD below the mean for gestational age

Answer 13

Severe micromelia

Question 14

Severely hypoplastic thorax is aka

Answer 14

“bell-shaped” thorax in a coronal plane
“champagne cork sign” in sagittal

Question 15

Thoracic circumference that is less than the —– for GA is indicative of a lethal defect

Answer 15

5th percentile

Question 16

What is the most common LETHAL skeletal dysplasia

Answer 16

Thanatophoric dysplasia (the name is derived from the Greek word thanatophoros which means “death bearing”)

Question 17

Sono finds of Thanatophoric skeletal dysplasia

Answer 17

“CLOVERLEAF” skull aka KLEEBLATTSCHADEL
bowed femurs (“TELEPHONE RECEIVERS”
severe micromelia
hypoplastic thorax
platyspondyly
mild hypomineralization
Poly

Question 18

A rare and lethal form of short-limbed dysplasia

Answer 18

Achondrogenesis

Question 19

Sono finds of achondrogenesis

Answer 19

lack of vertebral ossification
severe micromelia
hypoplastic thorax
large head + or - decreased cranial ossification
poly
associated cleft lip/palate micrognathia

Question 20

A rare bone demineralization disorder resulting from low levels of serum and tissue alkaline phosphatase

Answer 20

Congenital Hypophosphatasia

Question 21

Sono finds of Congenital Hypophosphatasia

Answer 21

decreased mineralization of bones
severe micromelia with possible bowing of long bones

Question 22

A condition in which there are abnormally fragile bones with decreased mineralization, fractures in utero resulting in severe micromelia and irregularity of bones

Answer 22

Osteogenesis imperfecta Type II

Question 23

Osteogenesis imperfecta type II is familial in what way

Answer 23

Autosomal recessive

Question 24

Sono finds of osteogenesis imperfecta type II

Answer 24

Presence of FRACTURES or “thick” bones due to callus formation
severe micromelia
hypoplastic thorax
multiple rib fractures
severe hypomineralization of the skull

Question 25

A rare lethal dysplasia characterized by polydactyly and an extremely small thorax (death is a result of respiratory insufficiency)

Answer 25

Short-Rib polydactyly Syndrome

Question 26

Sono finds of Short-rib syndrome

Answer 26

polydactyly
narrowed thorax with short ribs
micromelia
other anomalies (cardiac, renal, clefts, other)

Question 27

Asphyxiating thoracic dystrophy is aka

Answer 27

Jeune syndrome

Question 28

Rare autosomal recessive disorder that shares many of the features of short rib poly syndrome, the main prenatal feature being a small and narrow thorax

Answer 28

Asphyxiating thoracic dystrophy aka JEUNE SYNDROME

Question 29

Skeletal dysplasia that is characterized by short bent or bowed bones

Answer 29

Campomelic dysplasia

Question 30

Sono finds of campomelic dysplasia

Answer 30

“bent” long bones, especially the lower ext bones
narrow thorax
associated CNS and renal anomalies

Question 31

Sono finds of the lethal short-limbed dysplasia Homozygous Dominant Achondroplasia

Answer 31

Rhizomelia
TRIDENT HAND - short fingers with separation between 3rd and 4th fingers
small thorax with pulmonary hypoplasia
large cranium, possible cloverleaf

Question 32

What is the most common form of genetic skeletal dysplasia

Answer 32

Achondroplasia

Question 33

What type of osteogenesis imperfecta is the most common

Answer 33

Type I

Question 34

What type of OI is not detected prenatally

Answer 34

Type IV

Question 35

Term for more than the normal number of digits on the hand or foot

Answer 35

Polydactyly

Question 36

Skeletal dysplasia that is associated with deformation of the joints

Answer 36

Arthrogryposis

Question 37

Hypoplasia or aplasia of the radius

Answer 37

Radial ray abnormalities

Question 38

Permanent curvature of the 5th digit (secondary to hypoplastic middle phalanx)

Answer 38

Clinodactyly (associated with TRISOMY 21)

Question 39

Fusion of digits, either soft tissue or bony fusion

Answer 39

Syndactyly

Question 40

Another term for clubfoot is

Answer 40

Talipes equinovarus

Question 41

What two factors contribute to talipes

Answer 41

Genetics and environmental

Question 41

What two factors contribute to talipes

Answer 41

Genetics and environmental (Oligo, amniotic band syndrome, uterine tumors)

Question 42

Term for when the bottom of the foot convexes outward. This defect is associated with trisomy 18

Answer 42

Rocker bottom foot

Question 43

Term for fusion of the lower ext and abnormal or absent foot structures

Answer 43

Sirenomelia

Question 44

What is another name for Sirenomelia

Answer 44

Mermaid syndrome

Question 45

Sono finds of sirenomelia

Answer 45

single femur or two femurs constantly seen side by side
associated bilateral renal agenesis
oligo