FETAL MSK

limb bud can be seen by

7 weeks

rhizomelia

shortening of proximal segment (femur, humerus)

mesomelia

shortening of middle segment (radius, ulna, tibia, fibula)

acromelia

shortening of distal segment (hands, feet)

micromelia

shortening of entire limb

thoracic dysplasia

abnormally small misshapen chest associated with pulmonary hypoplasia

what is first bone in fetal limb to develop

humerus

what is the m/c non lethal skeletal dysplasia

achondroplasia

what is the m/c lethal skeletal dysplasia

thanatophoric dysplasia

homozygous achondroplasia

lethal

achondroplasia

• large head with prominent forehead

• normal size torso

• short arms and legs

• trident hand

• flattened nasal bridge

thanatophoric dwarfism

extremely short limbs, fold of extra skin, narrow chest, short ribs, underdeveloped lungs, enlarged head, wide space eyes

thanatophoric dwarfism type 1

• curved thigh bones

• flattened spine bones (platyspondyly)

thanatophoric dwarfism type 2

• straight thigh bones

• cloverleaf skull

what m/c has cloverleaf skull

thanatophoric dysplasia

platyspondyly

flattened vertebral bodies throughout axial skeleton

achondrogenesis

most severe degree of limb shortening

hypomineralized bone

subject to fractures, appears less echogenic than normal

hypophosphatasia

affects development of bones and teeth

what is the m/c anomaly associated with fetal fractures “brittle bones”

osteogenesis imperfecta

what type of osteogenesis imperfecta is lethal

type 2

caudal regression

impairs development of lower (caudal) half of body

• forg-leg position

• club feet

amniotic band syndrome

entrapment of fetal parts in amniotic bands

camptomelic dysplasia

bent bone

• bowing of long bones

roberts syndrome

phocomelia and facial anomalies

ellis-van creveld syndrome

increased frequency in amish community

radial ray

polydactyly

hand or foot with more than 5 digits

clinodactyly

inward curvature of 5th digit of the hand

persistently clenched hand is associated with

trisomy 18

syndactyly

congenital fusion of two or more digits

abnormal deviation of the foot in relation to tibia adn fibula

clubfoot

rocker bottom foot

abnormal curvature of pedal arch

• associated with tri 18

sandal foot

increase in space between great toe of foot and rest of the toes

• associated with tri 21