The different abnormalities of the fetal skeleton as seen in the ultrasound scans

1. SKELETAL AND LIMB
ANORMALIES
GROUP THREE
B ASSANDA W I NNIE
MUKO SE CH RI STI AN
NTAL E J OHN REAGAN
MEB RO N B I I RA
B AL I KI I S NAMUL I NDW A
AI SH A W ANYANA
BAL YAMA SHADIA
AKI RA SUSAN L AURA
KI RENZI UTH MAN

2. Introduction
By the end of the embryonic period, the differentiation of bones,
joints, and musculature is similar to that of an adult and is
associated with increased fetal movements.
Transvaginal ultrasound can demonstrate the limb buds by 7
weeks’ gestation, and the foot and hand plates are visible by 8
weeks. In second trimester the fetal skeleton is developed and
can be assessed.
Although measurement of all the long bones is not required in a
routine obstetric ultrasound, an overall evaluation of the fetal
skeleton should be performed to ensure the presence and
bilateral symmetry of the tubular bones.
 the sonographer should take note of bilateral limbs; both lower
and upper, the calvarium and facial bones, the spine; considering
their anatomy and density.
Through this evaluation, one can rule out skeletal and limb
anomalies. NTALE J.R/ WINNIE.B

3. Cont…
 Anomalies refer to an abnormal development of a specific or
group of organs.
 In this case the skeletal system; bones.
 These anomalies can occur with a single bone or in a group of
bones.
 There are more than 450 types of skeletal anomalies.
 However, not all of them are detectable on ultrasonography

4. Causes
The cause is idiopathic.
However possible causes include:
 Genetic factors.
 Chromosomal abnormalities
 Environmental factors like:
 Mechanical factors
 drugs
 Radiations
 Maternal nutrition factorsmaternal disease

5. Categories.
 Skeletal anomalies are either; dysplasia, dysostoses or
disruptions.
 The skeletal dysplasia are generalized developmental disorders of
chondro-osseous tissue caused by single gene disorders with
prenatal and postnatal manifestations.
 The dysostoses are single-gene disorders resulting in
malformations of a single bone or group of bones caused by
transient abnormalities of signaling factors.
 Disruptions are morphologic defects of an organ or larger region
resulting from extrinsic breakdown or interference with an
originally normal developmental process.

7. Skeletal Dysplasia
 Skeletal dysplasia exist as a large group of abnormalities of
skeletal system.
 More than 271 skeletal dysplasias have been identified.
 The four most common skeletal dysplasias are:
 Achondroplasia,
 Achondrogenesis,
 Osteogenesis imperfecta, and
 Thanatophoric dysplasia
The two classification of skeletal dysplasia are:
 Lethal skeletal dysplasia
 Non-lethal skeletal dysplasia
 BALIKIIS.N

8. Cont…
Lethal skeletal
dysplasia
 Thanatophoric
dysplasia
 Achondrogenesis
 Osteogenesis
imperfecta ii
 Hypophosphatasia
 Compomelic dysplasia
 Short rib polydactyly
syndrome
 Asphyxiating throracic
dysplasia
 Etc.
Non-lethal Skeletal
dysplasia
 Heterozygous
achondroplasia
(commonest)
 Diastrophic dysplasia
 Ellis-van creveld
syndrome
 Chondrodysplasia
punctata
 Dyssedmental
dysplasia
 Osteogenesis
imperfecta I,iii &iv
 Etc.

9. Ultrasound protocol for suspected
skeletal dysplasia
 When a skeletal dysplasia is suspected, the protocol of the obstetric
ultrasound examination should be adjusted to include the following
criteria:
1. Assess limb shortening. All long bones should be measured. A skeletal
dysplasia is suspected when limb lengths fall more than 2 standard
deviations below the mean.
2. Assess bone contour and density. Thickness, abnormal bowing or
curvature, fractures, and a ribbon-like appearance should be noted.
3. Estimate degree of ossification. Decreased attenuation of the bones
with decreased shadowing suggests hypo mineralization. Special
attention should be focused toward this assessment of the cranium,
spine, ribs, and long bones.
4. Evaluate the thoracic circumference and shape. A long, narrow chest
or a bell-shaped chest may be indicative of specific dysplasia
 5. Survey for coexistent hand and foot anomalies, such as talipes and
polydactyly.

10. Achondroplasia
This is a type of dwarfism in which the proximal
portions of limbs, the humerus and femurs are much
shorter than the distal portion of the limbs, a
condition known as rhizomelia
It results from decreased endochondral bone
formation which produces short, squat bones.
It is most commonly the result of a spontaneous
mutation but can also be transmitted in an
autosomal fashion.
Advanced paternal age increases the risk for this
dysplasia.
WINNIE.B/ NTALE.J.R

11. Achondroplasia…….
 The prognosis for achondroplasia depends on
the form.
Forms of achondroplasia include:
Heterozygous achondroplasia
 Inherited from one parent, has a good
survival rate with normal intelligence and a
normal life span.
 Health problems may include neurologic
complications that may require orthopedic or
neurologic surgical intervention.

12. Forms of achondroplasia…….
Homozygous achondroplasia,
 inherited from two parents, is considered
lethal, with most infants dying shortly after
birth from respiratory complications
With this form, sonographic findings are more
severe and include a narrow thorax
Rhizomelia
 is typically not detected until after 24 weeks
gestation when noticeable difference in the
gestational age measurements between the
biparietal diameter and femur length is
detected.

13. Achondroplasia….
Sonographic findings
 Trident hand
 Frontal bossing
 Macrocrania
 Flattened nasal
bridge
 Micromelia
(resulting from
rhizomelia)

14. Frontal bossing
Flattened nasal bridge &
Macrocrania

15. Micromelia

16. Achondrogenesis
It’s a rare lethal condition resulting in absent
mineralization of the skeletal bones.
It is apparent when there is deficient ossification
of the fetal spine, pelvis ad cranium.
The fetus will suffer from severe limb shortening
and may have rib fracture
Type I is considered more severe and is
transmitted in an autosomal recessive mode.
Type II is less severe, is more common, and is the
result of a spontaneous mutation.
The prognosis for achondrogenesis is grim. It is a
lethal abnormality with infants either being stillborn
or dying shortly after birth from pulmonary
hypoplasia. SHADIA.B/CHRISTIAN.M

17. Achondrogenesis…….
Sonographic findings
 Severely shortened
limbs (micromelia)
 Absent mineralization
of the skull, spine,
pelvis, and limbs
 Large skull
(macrocrania)
 Narrow chest and
distended abdomen
 Polyhydramnios

18. Achondrogenesis…….

19. Achondrogenesis…….

21. 14 week scan of a fetus with achondrogenesis type 1B
The thoracic-cage is extremely narrow and a cystic hygroma

22. Osteogenesis imperfecta
 Commonly known as brittle bone disease, is a
group of disorders that result in multiple
fractures that can occur in utero.
 The fractures are as a result of decreased
mineralization and poor ossification.
 There are four types of osteogenesis
imperfecta: I, II, III, & IV
 Type II is the most severe and fatal,
characterised by severe multiple fractures in
utero, skull demineralization, (recognized by
lack of posterior shadowing), and decreased
fetal movements

23. Osteogenesis imperfecta…….
 Sonographic findings
 Demineralization of the
skull (transducer
pressure can alter the
shape of the skull)
 Multiple fractures
 Bell- shaped chest
 Extremities that may
be bowed, fractured.

24. Osteogenesis imperfecta…….

25. Osteogenesis imperfecta…….

27. Thanatophoric Dysplasia
It is the most common lethal skeletal dysplasia
The fetus will have a cloverleaf skull with frontal
bossing and hydrocephalus,
Shortened long bones will be bowed and have
prominent metaphyseal ends and take on a “telephone
receiver” shape
The thoracic and abdominal circumference will be
remarkably dissimilar, leading to a bell shaped chest.
It is considered a lethal anomaly with most infants
dying shortly after birth due to respiratory distress
as a result of pulmonary hypoplasia, which results
from the narrow thorax. SUSAN.L.A/UTHMAN.K

28. Thanatophoric Dysplasia……
Sonographic findings
The sonographic features of thanatophoric
dysplasia include the following:
• Severe micromelia especially of the
proximal bones (rhizomelia)
• Cloverleaf deformity (Kleeblattschädel
skull), which occurs as a result of
premature craniosynostosis and may be
associated with agenesis of the corpus
callosum

29. Cloverlea
f head
with
frontal
bossing
(arrows)
and
lateral
protrusion
in the
region of
the
temporal
bones
(arrowhea
ds).
Thanatophoric Dysplasia……

30. A shortened and bowed tibia (arrow) and fibula (arrowhead)
are noted. B. Severe shortening and bowing of the tibia
(arrow) is noted in this fetus
Thanatophoric Dysplasia……

31. Longitudinal
image of
fetus with
discrepancy
in size of
fetal chest
(arrows)
compared to
fetal
abdomen
(arrow
heads).
The Heart
(H) in the
chest
Thanatophoric
Dysplasia……

32. Type 1
(left)
Type 2
(right)
Thanatophoric Dysplasia……

33. CAUDAL REGRESSION SYNDROME
 Caudal regression syndrome may also be
referred to as sacral agenesis.
 Uncontrolled maternal pregestational
diabetes has a strong association with caudal
regression syndrome
Sonographic findings:
 Absence of the sacrum (sacral agenesis) and
coccyx (coccygeal agenesis)
 There may also be defects in the lumbar spine
and lower extremities like clubfeet.
 UTHMAN.K/SUSAN.L.A

34. A. Sagittal image of the fetal spine appears to abruptly
terminate at the level of the lumbar spine (arrow) with
absence of the sacrum.
B. This fetus also had a clubfoot (arrow).
Caudal regression syndrome……..

35. Limb abnormalities
 The individual limb abnormalities are often features of
more complex genetic disorders or the results of other
causes including maternal teratogen exposure and
amniotic band syndrome.
 So limb abnormalities are not life threatening and the
prognosis depend on whether other disorders are
involved.
They are divided into 3 groups
 Focal absence
 Bone shortening
 Contractures and postural deformities
 AISHA.W/MEBRON.B

36. Focal absence
 Sirenomelia – fusion of the legs
 Ectrodactly – absence of fingers or toes
 Hemimelia - absence of distal part of the
limb (extremity) below the knee or elbow
 Phocomelia – absence of long bones with the
hand and feet arise from the shoulders and
hip.
 Syndactyly – fusion of digits ( webbed toes)

37. Bone shortening
Rhizomellia: shorting
of proximal segments
Mesomelia: shortening
of middle segments
Acromelia: shortening
of distal segments
Micromelia:
shortening of entire
limb

38. Contractures and postural deformities
 Polydactyl: having more than the normal
number of digits
 Talipes (clubfoot): An inversion of the soles
of one foot toward the other equinovarus
 Sandal gap: exaggerated distance between
the first toe and second
 Trident hand: increase space between the
third finger and fourth finger

39. Cont…
Artrogryposis: congenital joint contractures
of extremities
Clinodactly: deviation of a finger (overlapping
digits)
Equinus: extension of the foot (ankle joint is
limited)
Pterygium: web of skin across a joint
Valgus: a deformity in which the bone
segment distal to a bone bent outward

40. Pterygium
PTERYGYIUM
CLINODACTYL

41. ARTROGRYPOSIS
VALGUS

42. Sirenomelia
 This is also known as mermaid syndrome
because of the fusion of the lower
extremities that occurs with this disorder
 It is a rare and lethal abnormality that has
been associated with uncontrolled maternal
diabetes, monozygotic twinning and maternal
cocaine use.
 It is characterized by both lower extremities
fusion or a single lower extremity and renal
agenesis that results in severe
oligohydramnios.
 MEBRON.B/AISHA.W

43. cont…..
Sonographic
findings
Fusion of the
lower
extremities
Bilateral renal
agenesis
Oligohydromnio
s (possibly
anhydramnios)

44. Ectrodactly
Sonographic findings: Absence of finger or toes

45. Hemimelia
Sonographic findings
Absence of distal
part of the limb
(extremity) below
the knee or elbow
e.g.
 Fibula hemimelia
(commonest)
 Tibia hemimelia
 Ulna hemimelia
SHADIA. B

46. Phocomelia

47. Sandal gap
 Exaggerated distance between the first toe and second toe

48. Syndactyly
Fusion of digits
(e.g., webbed toes)

49. Polydactyl
 This is the presence of extra digits on the fetal
hands or feet.
 It is one of the most common hand anomalies and may
occur as an isolated finding or as part of a syndrome.
 Polydactyly can be classified according to the location
of the extra digits.
 Pre-axial polydactyly affects the radial (thumb) side
 Post-axial polydactyly affects the ulna (little finger)
side
 Central polydactyly affects the three central digits.
Sonographic findings:
Presence of an extra digit on the hand or the
foot
 UTHMAN.K

50. Polydactyl…

51. Club foot (talipes equinovarus)
 Malformation of one of the foot or
both
 The foot is most often rotated
medially,
 The sonographic diagnosis of
clubfoot can be made when the
metatarsals lie in the same plane as
the tibia and fibula
Sonographic findings
 Both tibia and fibula may appear in
the same image as medially deviated
foot.
 SUSAN.A.L

53. Thrombocytopenia Absent Radius
 This is an autosomal recessive disorders associated
with decreased platelets level.
 It is characterized by bilaterally absent radii but
five fully formed digits.
 Other abnormality of the upper limbs may be
presents and this condition is often associated with
congenital heart disease.
 Prognosis is very poor in many cases because of
intracranial hemorrhage.
 Differential diagnosis for TAR includes
 Holt- Oram syndrome and Roberts syndrome.

54. Thrombocytopenia Absent Radius…….
Sonographic findings
 Bilateral
absence of radii
with normal or
absence of
thumbs.
 Unilateral renal
agenesis
BALIKISS/CHRISTIA
N

55. References
 Examination review for Ultrasound Abdomen
and Obstetrics & Gynecology
 Radiopedia
 Internet
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