Pelvis: Acetabulum


Pelvis: Acetabulum

Table 5.18 Pelvis: increased acetabular angle




Developmental dysplasia of the hip

Fig. 5.20a–c

Fig. 5.21, p. 508

Hypoplastic acetabular roof with later development of increasing sclerosis. Posterosuperior dislocation of the femoral head ± flattening of the femoral head.

Ultrasound (US) is the screening modality of choice before ossification excludes visualization of the hip structures (below the age of 6 mo).

Secondary hip dysplasia

Increased acetabular angle. Shallow acetabulum. Coxa valga, ± femoral head dislocation and flattening.

Generally occurs in neuromuscular diseases with spasticity of the lower extremities. May develop in a previously normal hip.


Very thin diaphyses, osteopenia, dislocation and subluxation of large joints.

Joint contractures and decreased muscle bulk.

Ehlers-Danlos syndrome types III and VII

Hip dislocation with an otherwise normal appearing skeleton.

Calcified round areas of subcutaneous fat necrosis.

Campomelic dysplasia

Fig. 5.14, p. 501

(see Table 5.12 )

Larsen syndrome

Accessory carpal ossification centers, double calcaneal ossification center. Dislocation of large joints.

Flat facies. Clinical DD: Marfan syndrome, arthrogryposis, and Ehlers-Danlos syndrome.

Fig. 5.20a–c Developmental dysplasia of the left hip with dislocation and delayed ossification of the proximal femoral epiphysis (a). (b) US shows dislocation. (c) Normal side for comparison.
Fig. 5.21 Developmental dysplasia of the left hip with a shallow acetabulum.

Lateral and Medial Spurs of the Acetabulum (Trident Acetabulum) Acetabular Protrusio

Spurs are seen in skeletal dysplasias when the base of the iliac bone is small and the entire iliac bone is decreased in size. The spur is visible in neonates and young infants and disappears as the skeleton matures.

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Jul 12, 2020 | Posted by in PEDIATRIC IMAGING | Comments Off on Pelvis: Acetabulum

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