Normal fetal skeletal system

Axial skeleton consists of

cranium, facial bones, pelvis and spine

Appendicular skeleton consists of

Long bones and extremities

All long bones can be evaluated by

15-16 weeks

Epiphyseal plates are not ossified until after

30 weeks

Femoral diaphysis length can be reliable used for dating after ___ weeks

14

The femur grows __ mm per week in 2nd tri and __mm a week in 3rd tri

2; 1

A femur length >2 SD below expected GA indicates:

Possible skeletal dysplasia

Lower legs should be evaluated with ankle joint in _______ plane to r/o ankle/foot deformities

Sagittal

Foot measurements

Should be taken from the axial view placing the calipers on longest toe to tip of heel

Comparison of what two bones is necessary if foreshortening is suspected?

Femur and humerus

Middle phalanx of the 5th digits of the hand is measured when

Trisomy 21 is suspected

Each finger has __ bones (prox. middle and distal phalanx)

3

Polydactyly

More than 5 digits

Syndactyly

Fusion of digits, tissue (webbing) and/or bone

Clinodactyly

Abnormal curvature of 4th and 5th digits following angle of palm of hand

Ectrodactyly

Lobster claw hand

Sandal gap

Excessive gap between 1st and 2nd toe

Trident hand

Excessive gap between 3rd and 4th fingers

Amelia

Absence of extremity

Acromelia

Foreshortening of bones of hands and feet

Rhizomelia

Shortening of proximal bones of extremity

Mesomelia

Shortening of distal long bones of extremity

Micromelia

Shortening of both segments of extremity

Phocomelia

Absence of long bone segments of an extremity so hand/foot from shoulder/hip

Hemimelia

Absence of longitudinal segment of a limb

Acheria

Absence of hands

Apodia

Absence of food/feet

Acheiropodia

Absence of hands and feet

Ankle imaging is preferred using the _______ plane, while assessing foot length is preferred using the ____ plane

Sagittal; Axial

Humerus is best identified by locating the ________ and rotating the transducer to view the humerus

Scapula