Skeletal dysplasia musculoskeletal radiology is very concise and it cover the all-important topic of skeletal dysplasia with their characteristic feature and radiological findings with a proper radiographic image. Starting from classification and approach. It includes nosology classification. Thanks.

1. Skeletal dysplasia
Pradeep Kumar

2. • Skeletal dysplasia (also known as osteochondrodysplasia) refers to
any abnormality in bone formation. There is a very wide
clinicopathological spectrum and any part of the skeleton can be
affected.
• Epidemiology
• The overall prevalence is estimated at ~2 per 10,000 live births .
• Pathology
• Types
• One way of broadly classifying them is into limb deficiency, limb
shortening/dysplastic or non-limb shortening types. Another way of
categorising is by whether the dysplasia is sclerosing or non-sclerosing.

3. Limb deficiencies
• Amelia: complete limb absence
• Meromelia: partial limb absence
• Limb shortening/dysplastic
• Rhizomelic dwarfism
• Rhizomelic dwarfism is characterised by limb shortening, being
most notable proximally:
• Achondroplasia (most common short-limbed dwarfism)
• Thanatophoric dysplasia
• Osteogenesis imperfecta
• Rhizomelic chondrodysplasia punctata
• Asphyxiating thoracic dysplasia (Jeune disease)

4. Non-rhizomelic dwarfism
• Non-rhizomelic chondrodysplasia punctata: Conradi-
Hunermann syndrome
• Diastrophic dysplasia
• Campomelic dysplasia
• Chondroectodermal dysplasia / Ellis-van Creveld syndrome
• Kniest dysplasia
• Achondrogenesis
• type I
• type Ia: Houston-Harris subtype
• type Ib: Parenti-Fraccaro subtype
• type II: Langer-Saldino syndrome
• Spondyloepiphyseal dysplasia
• Multiple epiphyseal dysplasia: mild limb shortening
• Hypochondroplasia
• Metaphyseal chondrodysplasia
• Schmid type
• Pena and Vaandrager type
• Jansen type
Non-limb shortening
•Pyle disease: metaphyseal
dysplasia
•Progressive diaphyseal
dysplasia: Camurati-
Engelmann disease

5. Approach to skeletal dysplasia
1. Does the abnormality affect the proximal (rhizomelic), middle
(mesomelic), or distal (acromelic) segment? Acromesomelic
Rhizomelic- metatropic dysplasia, achondrogenesis,
rhizomelic chondrodysplasia punctata, achondroplasia, thanatophoric
dysplasia
Mesomelic -dyschondrosteosis (Leri-Weil disease): limb shortening with a Madelung
deformity
Acromelic -asphyxiating thoracic dysplasia/Jeune's syndrome:
Acromesomelic-chondroectodermal dysplasia - Ellis-van Creveld syndrome
2.Is polydactyly, clinodactyly, or syndactyly present?(asphyxiating thoracic
dysplasia, Ellis-van Creveld syndrome - chondroectodermal dysplasia, syndactyly -Apert
syndrome, cruzon, down syndrome, clino- Turner and down syndrome
3.Are there any fractures, curved bones, or joint deformities? Fracture- OI

6. 4.Are metaphyseal changes present?( Thantophoric dyplasia,
achrondroplasia, hypochondroplasia, Jeune disease
5.Are there any hypoplastic or absent bones?

7. 1.Is the spine short because of missing parts (eg, sacral agenesis)?
2. Is there abnormal curvature? (Scoliosis)
3. Is there shortening of vertebral bodies?
4.Are all parts of the spine equally affected?
(achondrogenesis)
5.Is platyspondyly present (thanatophoric dysplasia)?

8. 1.Is the thorax extremely small (thanatophoric dysplasia)?
2.Is the thorax long and narrow (Jeune syndrome)?
3.Are the ribs extremely short (short-rib polydactyly)?
4.Are fractures present (osteogenesis imperfecta type II)?
5.Is there clavicular aplasia, hypoplasia, or partitioning (cleidocranial
dysostosis)?
6.Is the scapula normal or abnormal (camptomelic dysplasia) ?

9. Limb lengths:
• Rhizomelia
(humerus and femur)
• Mesomelia
(radius, ulna, tibia and
fibula)
• Acromelia (Hands
and feet)

10. • Spine assessment for kyphosis, scoliosis and lordosis is also important
Clinical assessment is also very important like
Mental retardation - Chondrodysplasia punctata
Dental deformities - CCD
Disproportionately large head – Achondroplasia, Thanotophoric dysplasia
Congenital cataract - Chondrodysplasia punctata
Myopia - SED congenita
Renal involvement – Asphyxiating thoracic dysplasia

17. Radiology : skeletal survey
Skull (AP and lateral) to include atlas and axis
Spine (AP and lateral)
Chest (AP)
Pelvis (AP)
One Upper limb (AP)
One Lower limb (AP)
Hand (bone age)AP
Feet (AP) Additional views
Lat knee for patella
Lat foot for calcaneum
• In cases with epiphyseal stippling/limb asymmetry- B/L limbs

18. • In preterm fetuses and stillbirths, babygram i.e. anteroposterior
(AP) and lateral films from head to foot
• Imaging of other family members suspected of having same
condition

19. A – Anatomical localisation : axial / appendicular/ combinations
B – Bones
C – Clinical assessment and Complications

20. A - Anatomical localization
Dysplasia with involvement of axial skeleton

21. Dysplasias with involvement of appendicular skeleton
Type of shortening Examples Location of
abnormality
Examples
Rhizomelic Achondroplasia
Spondyloepiphyseal
dysplasia congenita
Epiphyseal Chondrodysplasia
punctata
Spondyloepiphyseal
dysplasia
Mesomelic Mesomelic dysplasia Metaphyseal Achondroplasia
Chondroectodermal
dysplasia
Acromelic Acrodysostosis Diaphyseal Progressive
diaphyseal dysplasia
Micromelic Achondrogenesis Combination Spondylo-
epimetaphyseal
dysplasia Metatropic
dysplasia

22. ACHONDROPLASIA
Achondroplasia belongs to group 1 of the
osteochondrodysplasias, as listed in the
International Nosology and Classification of
Genetic Skeletal Disorders.
Antenatal diagnosis (by ultrasonography) is
possible by detecting shortening of the long
bones. Short limbs (specifically short
femora) are not apparent until toward the end
of the first (homozygous disease) or second
trimester (heterozygous disease).
• Radiologic findings for the include:
1. Skull: Large vault; small foramen magnum
2. Spine: Bullet-shaped vertebral bodies with
posterior vertebral scalloping

23. 3. Chest: Small
thorax with short
ribs
4. Pelvis: Medial and
lateral acetabular
spurs (trident
acetabula);
horizontal
acetabular roof;
small sacrosciatic
notch

24. •
5. Long bones:
Characteristic sloping
metaphyses—especially
of proximal femora

25. • 5.
Hands:
Trident;
bullet-
shaped
phalange
s

27. THANATOPHORIC DYSPLASIA
• This is the most common lethal osteochondrodysplasia and belongs to the
achondroplasia group (group 1) of the International Nosology.
• It results from a sporadic AD FGFR3 mutation. Antenatal diagnosis is based
on identification of short, bowed femora in association with a small thorax.
Radiologic findings include:
1. Skull: Relative macrocephaly; in type 1 the skull is of normal shape; in
type 2 there is premature fusion of the temporoparietal sutures an
frontal bossing, giving rise to the “cloverleaf” skull or
Kleeblattschädel

29. 2. Spine: Severe platyspondyly
with “wafer thin” or
H-shaped vertebral bodies
3. Chest: Small thorax; short
horizontal ribs with cupped
costochondral junctions
4. Pelvis: Small, square iliac
wings; small sacrosciatic notch;
trident acetabula
5. Long bones: Significant
micromelia; irregular, flared
metaphyses; bowed “telephone
receiver” femora

30. 6. Hands:
Short,
broad
tubular
bones

31. Classic sign of
hypochondroplasia
• Autosomal-dominant inheritance
• Usually less severe than
achondroplasia
• No change or decrease in
interpedicular distance from L1 to
L5
• Short, relatively broad long bones
• Long distal fibula
Classic sign of Thanatophoric
dysplasia
• Most common lethal
osteochondrodysplasia
• Type 1 has normal skull shape
• Type 2 has a “cloverleaf “ skull
• Classic bowed (“telephone receiver”)
femora are not universal

35. Classic sign of Jeune thoracic
dystrophy
• Nonlethal, autosomal recessive short rib
syndrome; perinatal death from lung
hypoplasia may occur
• Those who survive infancy develop renal
cystic disease andmay die of renal
failure
• Trident acetabula
• Postaxial polydactyly in 10% of patients
• Metaphyseal spurs
• Cone-shaped epiphyses of hands

37. • There are autosomal-recessive and
autosomal-dominant forms of MED
• Patients present with joint stiffness,
pain, and premature osteoarthritis
• There is delayed appearance of small
fragmented epiphyses of hips, knees,
and hands.
• A multilayered patella is
characteristic of autosomal-recessive
MED

42. • This is the mildest and most
common metaphyseal
chondrodysplasia
• Major differential diagnosis is
rickets, but bone density is
normal
• Lower limbs are most severely
affected

43. • Spondyloepiphyseal dysplasia tarda
comprises a heterogeneous group of
conditions
• X-linked spondyloepiphyseal dysplasia
tarda presents in early childhood
• Affected males have arm span greater than
height (short trunk)
• The main symptoms are back and hip pain
and stiffness
• The characteristic radiographic finding is
humps in the posterior two thirds of the
vertebral bodies (best seen between ages 4
and 12 years)
Spondyloepiphyseal dysplasia

44. • Inheritance is autosomal-dominant with
variable expression, and it is more severe in
females
• Long bones: Mesomelic shortening
• It is characterized by mesomelic shortening
and Madelung deformity
• Madelung deformity may occur as an
isolated condition

45. • Autosomal-dominant disorder
caused by mutation in SOX9
gene
• Often perinatally lethal due to
respiratory insufficiency
• Survival may occur in those
with mild or mosaic mutations
• Angulated long bones (with
no shortening) and absent
wings of scapulae in neonates
• Hypoplastic patellae, absent
ossification of inferior pubic
rami, hypoplastic scapular
wings, and kyphoscoliosis in
survivors

47. • X-linked dominant condition
(Conradi-Hünermann)
• Antenatal diagnosis is possible
• Characterized radiologically
by stippled calcification of
cartilage
• Stippling of the long bones is
asymmetric, leading to
asymmetric long-bone
shortening

48. • Prenatal autosomal-recessive form is severe
and lethal
• Prenatal autosomal-dominant type is milder
• Postnatal autosomal-dominant type has
median onset at 9 weeks of age
• There is painful swelling of affected sites with
associated systemic symptoms
• Jaw, ribs, and long bones are commonly
affected
• Radiographs reveal florid periosteal reactions

50. OSTEOGENESIS IMPERFECTA
• The characteristic radiologic features of OI are reduced bone density, multiple fractures,
slender ribs and long bones, and multiple wormian bones.

51. Radiologic findings of types I, III, and IV OI
include:
1. Skull: Deficient mineralization; wide sutures;
multiple wormian bones , platybasia with “Tam
O’Shanter” , basilar invagination; and cord
compression
2. Long bones: Extremely slender; multiple
fractures on minimum handling; limb deformities
3. Spine: Codfish vertebrae , kyphoscoliosis
4. Pelvis: Protrusio acetabuli

54. CLASSIC SIGNS OF OSTEOGENESIS IMPERFECTA
• Mainly autosomal dominant except type III (both forms) and type VII (autosomal
recessive)
• Blue sclerae occur in type I (mild)
• Type II is perinatally lethal
• Type III is the severe deforming type
• White sclerae occur in type IV (ranges from mild to severe)
• The presence of normal teeth or dentinogenesis imperfecta
divides types I and IV into subtypes A and B, respectively
• If fractures are occurring in infants with type IV OI, then
reduced bone density should be apparent on radiographs
(normal bone density in nonaccidental injury)
• Type V is associated with hypertrophic callus formation and
elbow dislocation
• Type VI has characteristic histology
• Type VII is associated with rhizomelic shortening
• Bisphosphonate therapy leads to characteristic dense metaphyseal bands

55. MPS (Mucopolysaccharidoses)
• Group 27 of the International Nosology consists of those lysosomal storage disorders
with skeletal involvement

56. Radiological findings
1. Skull: Macrocephaly; ground-glass opacity of the skull vault; elongated/J-
shaped sella turcica
2. Face: Flattening of mandibular condyles
3. Chest: Broad ribs with posterior constriction—“oar/paddle-shaped” ribs; broad
clavicles
4. Spine: Hypoplasia at thoracolumbar junction; kyphosis; oval vertebral bodies
with central tongues or inferior beaking ,posterior scalloping; platyspondyly is
severe in type IV , hypoplastic odontoid peg in type IV.
5. Pelvis: Narrow; flared iliac wings; dysplastic acetabula
6. Long bones: Generalized epiphyseal dysplasia; fragmented proximal femoral
epiphyses in type IV ,coxa valga; elongated femoral necks , genu valgum in type
IV
7. Hands: Reduced carpal angle; short broad (“sugarloaf”) metacarpals; short
broad phalanges; pointed base of second to fifth metacarpals

57. • All the mucopolysaccharidoses
are autosomal recessive
except for type II (Hunter disease),
which is X-linked recessive
• Corneal clouding in types I and VI
• Behavioral disturbance in type III
• Normal intelligence, a normal
skull, hypoplastic odontoid
peg, severe platyspondyly, and genu
valgum in type IV
• Type VII may present in utero as
hydrops fetalis
Classic sign of MPS

61. • Ollier disease and Maffucci
syndrome are nonhereditary
sporadic conditions
• Maffucci syndrome is the
association of multiple
enchondromas with venous
malformations
• The incidence of
malignancy is increased in
both conditions,
reaching 100% in older
patients with Maffucci
syndrome

63. • Sporadic condition
• May be associated with
multiple café-au-lait macules
• May be associated with
endocrine disturbances
• Nonaggressive expansile
lesions with well-defined
sclerotic margins and central
ground-glass opacification
• Overgrowth of bones is a
feature leading to leontiasis
ossea
when skull and facial bones are
affected
• Bone softening leads to
bilateral progressive coxa vara
(shepherd’s crook deformity

65. Sclerosing dysplasia
MELORHEOSTOSIS

66. OSTEOPATHIA STRIATA
• Characteristic findings are linear bands
of dense bone in the metaphyses and
diaphysis of long bones.
• Osteopathia striata often show
evidence of other conditions that cause
increased bone density, such as
melorheostosis and osteopetrosis

67. OSTEOPETROSIS
Radiologic Features
Severe AR osteopetrosis presents at birth with generalized
osteosclerosis.
The intermediate (juvenile) type of osteopetrosis is
characterized radiographically by a “bone-in-bone”
appearance of all bones with increased chance of fracture.
Autosomal-dominant (adult) osteopetrosis may present
as an increased tendency to fracture and incidentally
detected.
Type I has generalized osteosclerosis most pronounced in
the cranial vault; it is not associated with an increased
tendency to fracture.
Type II typically Sclerosis in spine (“rugger jersey” spine,
pelvis, and skull base with increased tendency to fracture

69. • Increased bone density with fragile bones due to
abnormal osteoclast function
• Timely bone marrow transplantation in the
severe infantile autosomal-recessive type is
curative
• Intermediate type is characterized by “bone-in-
bone” appearance of entire skeleton
• Adult type may be an incidental finding; those
with type I autosomal-dominant osteopetrosis do
not have an increased tendency to fracture

72. OSTEOPOIKILOSIS
• This uncommon but interesting
bone disorder was first described
by Albers-Schönberg and by
Ledoux-Lebard and Chabaneux.
• Osteopoikilosis is characterized by
small round or ovoid radiopacities
appearing in the juxtaarticular
regions of bone.
• It has been described as autosomal
dominant inheritance.

74. PYKNODYSOSTOSIS
Radiologic Features
1. Skull: Prominent vault; multiple wormian bones; wide
open sutures and fontanelles; obtuse or absent mandibular
angle
2. Chest: Resorption of lateral ends of clavicles; slender
clavicles
3. Pelvis: Narrow iliac bones with normal ossification of
pubic bones
4. Spine: Dense vertebral bodies, with or without
spondylolisthesis. Spool-shaped vertebrae and
persistence of anterior infantile notching are
frequently present.
5. Hand: Resorption of the terminal phalanges

76. MARFAN’S SYNDROME
• Marfan’s syndrome is an autosomal dominant
entity consisting of long, slender tubular
bones, ocular abnormalities, and aortic
aneurysm
the skull reveals dolichocephaly. The face is
elongated, with a high, arched palate and
prominent jaw.
• The tubular bones of the hands and feet
are particularly long, slender, and gracile;
hence the term arachnodactyly or spider-like
fingers
• Acetabular protrusion, unilateral or bilateral.
• Posterior scalloping of the vertebral bodies
and thinning of the pedicles and lamina
secondary to dural ectasia

77. NAIL-PATELLA SYNDROME

78. EHLERS-DANLOS SYNDROME
The most characteristic
radiographic findings of
Ehlers-Danlos syndrome are
seen in the soft tissues
Calcified subcutaneous
spherules of necrotic fat
tissue.
Capsular and ligamentous
laxity, which results in
recurrent subluxations and/or
dislocations
Spinal changes include
platyspondyly and posterior
vertebral body scalloping.
Scoliosis and flattening of the
thoracic sagittal curve may be
seen

79. Turner’s syndrome

80. Clover leaf skull : thanatophoric dysplasia
Spatulated ribs : hurler
Vertebral bodies
1. wafer thin, platyspondyly (Thanatophoric dysplasia)
2. hooked(MPS)
3. bullet shaped ( achondroplasia)
4. spool shaped : pycnodysostosis
5. coronal clefts : chondrodysplasia punctata
6. heaped up vertebrae : SED tarda
7. Posterior scalloping of vertebral bodies
Acetabular roof
• sloping (MPS)
• horizontal roof (Achondroplasia)
Telephone handle femora : thanatophoric dysplasia

82. REFERENCES
• MUSCULOSKELTAL IMAGING BY POPE, BLEOM,BELTRAN et al. 2ND
EDITION
• YOCHUM AND ROWE SKELETAL RADIOLOGY 3RD EDITION
• SUTTON DIAGNOSTIC RADIOLOGY 7TH EDITION
• RADIOPAEDIA
• AJR/RSNA