Skeletal dysplasias: A radiographic approach and review of common non-lethal skeletal dysplasias

Table 1 Set of radiographs obtained in a skeletal survey[1]

Skull (AP and lateral)

Thoracolumbar spine (AP and lateral)

Chest (AP)

Pelvis (AP)

One upper limb (AP)

One lower limb (AP)

Left hand (AP) ( for bone age)

AP: Anteroposterior.

Table 2 Dysplasias with involvement of axial skeleton

Location	Examples
Skull	Achondroplasia, Cleidocranial dysplasia
Mandible	Pyknodysostosis
Clavicle	Cleidocranial dysplasia
Ribs	Asphyxiating thoracic dysplasia, Thanatophoric dysplasia
Spine	Spondyloepiphyseal dysplasia congenita, Mucopolysaccharidoses
Pelvis	Achondroplasia

Table 3 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 Mucopolysaccharidoses

Table 4 Differences between pseudoachondroplasia and achondroplasia

Pseudoachondroplasia	Achondroplasia
Skull: Normal: “Achondroplasia with normal face”	Skull : Abnormal
Spine: Platyspondyly +	Spine: Platyspondyly –
Interpedicular distance normal	Interpedicular distance decreased in lumbar spine
Epiphyses and metaphyses abnormal		Only metaphyses abnormal
Trident hand and champagne-glass pelvis absent	Trident hand and champagne-glass pelvis present

Table 5 Differences between Rhizomelic and Conradi-Hunermann type Chondrodysplasia punctata

Rhizomelic/lethal type	Conradi-Hunermann type
Inheritance: Autosomal recessive	Inheritance: X-linked dominant
Symmetric rhizomelic limb shortening	Asymmetric and occasional limb shortening
Stippling in spine absent/coronal clefts present	Spine: stippling present at endplates and bodies, later leads to kyphoscoliosis
Stippling noted in large joints, sparing hands and feet Laryngeal and tracheal cartilage stippling also present	Hands and feet also involved in addition to large joints. No extracartilaginous stippling
Mental retardation present and death in infancy	Compatible with normal intelligence and normal life span