Pelvic radiograph in skeletal dysplasias: An approach

Abstract

The bony pelvis is constituted by the ilium, ischium, pubis, and sacrum. The pelvic radiograph is an important component of the skeletal survey performed in suspected skeletal dysplasia. Most of the common skeletal dysplasias have either minor or major radiological abnormalities; hence, knowledge of the normal radiological appearance of bony pelvis is vital for recognizing the early signs of various skeletal dysplasias. This article discusses many common and some uncommon radiological findings on pelvic radiographs along with the specific dysplasia in which they are seen; common differential diagnostic considerations are also discussed.

Keywords: Achondroplasia; pelvic radiograph; skeletal dysplasia.

Figure 1

Normal pelvic radiograph in a full term newborn

Figure 2

Pelvis radiograph in achondroplasia shows square shape of the iliac bone, horizontal acetabular roof (squiggly arrow), and rhizomelic shortening of the femur. Also note the trident sign in achondroplasia. The three-pronged pear shape of the sciatic notch is well visualized in this radiograph (straight arrow)

Figure 3(A and B)

(A and B) Pelvis radiograph in mucopolysaccharidosis type I (A) reveals steep sloping of bilateral acetabular roofs (marked), which are irregular. Lumbosacral spine radiograph lateral view (B) of the same patient reveals localized angular kyphosis at the dorsolumbar junction and beak-like projection (arrows) from the inferior aspect of visualized thoracolumbar vertebral bodies (inferior beaking)

Figure 4(A and B)

Trident pelvis in Jeune's asphyxiating thoracic dystrophy. Pelvis radiograph (A) shows a flared iliac bone having a trident shape (marked) at sciatic notch. The chest radiograph (B) reveals that the ribs are small and thoracic cavity narrow

Figure 5(A and B)

(A, B) Campomelic dysplasia. Radiograph of pelvis (A) of the stillborn fetus shows apparent shortening of the iliac bone (thin arrow); and curved long bone of the lower limb (block arrow). Chest radiograph (B) revealed hypoplastic scapula (thick arrow) and bent radii and ulnae (thin arrows)

Figure 6

Dyggve-Melchior Claussen syndrome: Pelvic X-ray demonstrates bilateral iliac crest irregularity (squiggly arrows), wide sacroiliac joints (straight arrow), wide pubic, and ischial rami. Note dysplastic acetabular fossae with abnormally shaped and laterally displaced femoral heads (block arrows)

Figure 7

Ollier's disease. Pelvic radiograph shows the characteristic lace-like irregular lace-like configuration of the iliac crest margins on both sides (marked). Also of note are the multiple enchondromas in bilateral proximal femoral shafts (marked on left side) and right iliac wing, which point towards the right diagnosis

Figure 8

Representative illustration depicting relatively well ossified iliac bone with long crescent-shaped medial and inferior margins (arrows) typical of Paraglider shaped pelvis – classical finding seen in achondrogenesis

Figure 9

Representative illustration depicting extremely small, snail-shaped ilium (left) with a superomedial extension (arrow) resembling a snail's head – seen in Schneckenbecken dysplasia

Figure 10

Osteopathia striata. Radiograph of the pelvis showing alternating sclerotic bands in the iliac wings (marked)

Figure 11

Representative illustration depicting typical triangle-shaped excrescence arising from the posterior aspect of the ilium (posterior iliac horn)– classical finding seen in Nail–patella syndrome

Figure 12

Osteopetrosis. Radiograph of the pelvis reveals generalized sclerosis of the pelvic bones with loss of corticomedullary differentiation

Figure 13

Osteopoikilosis. Radiograph of the pelvis reveals multiple well defined sclerotic lesions around the pelvis arrows, especially centred around the joints

Figure 14

Chondrodysplasia punctata in another newborn. Pelvic radiograph shows extensive calcific stippling of sacrum and lower lumbar vertebrae (marked)

Figure 15(A and B)

Caudal regression syndrome. Lumbosacral spine AP radiograph (A) in a neonate shows absence of lower sacral vertebrae and coccyx. Lateral projection of lumbosacral spine in same patient shows presence of L1 vertebra (marked) with absence of remaining lower vertebrae

Figure 16

Cleidocranial dysostosis. Pelvic radiograph revealing retarded ossification of pubic bones resulting in widening of symphysis pubis (pseudo diastasis, asterisk). Also note the elongated shape of capital femoral epiphyses giving a “chef's hat” sign, along with coxa vara (arrows)

Figure 17(A and B)

SEDC with pelvic radiograph (A) demonstrating delayed ossification of bilateral femoral heads and horizontal configuration of acetabular roofs (squiggly arrow). Also note bilateral femoral metaphyseal flaring (straight arrows) and coxa vara. Radiograph of lumbosacral spine (B) in the same patient depicts anisospondyly (L4 vertebral body larger than L5 vertebral body) (arrow)

Figure 18

SEMD: Pelvic radiograph reveals imaging findings similar to SEDC, with metaphyseal flaring and coxa vara – note the prominent metaphyseal irregularity (arrow)

Figure 19

Pelvic radiograph in pseudoachondroplasia in a 10-year-old reveals wide triradiate cartilage (arrows) and small femoral head for age (block arrow)

Figure 20

Small capital femoral epiphyses in multiple epiphyseal dysplasia. Radiograph of the pelvis shows small and irregular bilateral femoral head (marked); akin to bilateral Perthe's disease. Radiograph of the knee (not shown here) showed irregular epiphyses around the knee joint, and a tibiotalar slant was apparent in ankle radiograph

Figure 21(A and B)

Pseudoachondroplasia – Pelvic radiograph (A) demonstrating metaphyseal flaring (block arrows), squared iliac wings, and horizontal acetabular roofs (squiggly arrow) akin to achondroplasia. Note that the femoral head are small (straight thin arrow). Also, in lateral spine radiograph (B), the tongue-shaped projection from the lumbar vertebrae (arrows) are a specific imaging finding in pseudoachondroplasia

Figure 22

Case of Desboqouis dysplasia – Anteroposterior radiograph of the pelvis showing “monkey wrench” appearance of both femora, elevated greater trochanters (thin arrows), coxa vara and dysplastic femoral epiphyses (thick arrow)

Figure 23

Irregular upper femoral metaphyses in McKusick type metaphyseal chondrodysplasia

Figure 24(A and B)

Spondylometaphyseal dysplasia Sutcliffe type – (A) Pelvis with hip joint anteroposterior radiograph reveals bilateral coxa vara and slipped capital femoral epiphyses (B) bilateral knee anteroposterior radiograph reveals metaphyseal fraying with corner fractures (arrows)

Figure 25

Juvenile hypothyroidism – Pelvic radiograph revealing unfused femoral head epiphysis and apophysis (small arrow) with perisistent triradiate cartilage (arrows) and irregular epiphyses (block arrows)

Figure 26

Pelvic radiograph in a case of fibrodysplasia ossificans progresiva reveals soft tissue ossification in bilateral thighs adjacent to femur (straight arrows) as well as in righ hemipelvis adjacent to right iliac wing (squiggly arrow)