Flared or Cupped Ribs

► [Wide, concave anterior rib ends]

Mild cupping of the anterior ends of the ribs may be a normal finding in premature infants. Rib cupping in full-term infants or older children usually accompanies a generalized skeletal disease, either a metabolic disorder or a bone dysplasia. As far as the metabolic disorders are concerned, rib flaring and cupping are consistently associated with rickets, which is related either to abnormalities of the vitamin D metabolism (dietary deficiency, gastrointestinal malabsorption, prematurity, liver disease, anticonvulsant therapy, renal osteodystrophy, parathyroid disorders) or to primary loss of phosphate at the renal tubuli (X-linked hypophosphatemia, Fanconi syndromes, neoplasms). Regardless of the cause, children with rickets have swelling of the costochondral junctions of the middle ribs with secondary inward protrusion ('rachitic rosary'), metaphyseal changes in the long bones (widening, cupping, fraying, fuzzy-looking margins, increased epi-metaphyseal distance), and rarefaction of the skeleton, most prominent in the metaphyseal regions, with thin cortices, course trabecular pattern, incomplete fractures, pseudofractures, and bowing of the long bones in the lower limbs (Fig. 2.29). In adults, radiologic manifestations include bowed long bones, broad bones with course trabecular pattern, incomplete fractures, and scoliosis. Given the similarities of the radiologic patterns, differentiation of individual forms of rickets depends upon the biochemical findings. Abnormalities of copper metabolism (nutritional copper deficiency, Menkes syndrome) is also consistently associated with rib cupping and widening. Both nutritional copper deficiency (hypocupremia) and Menkes kinky hair syndrome (OMIM 309400) show osteoporosis, irregularly dense, cup-shaped provisional zones of calcification, peripheral spurs in continuity with the provisional zone of calcification, flared ribs, epiphyseal displacement, multiple fractures, subperiosteal hemorrhage, periostitis, subpe-riosteal calcifying hematomas, and bone age retardation (Allen et al. 1982; Stanley et al. 1976). These manifestations, which may be reversed when the diet is supplemented with copper, are similar to those occurring in vitamin C (ascorbic acid) deficiency, or scurvy (Hallel et al. 1980).

Rib flaring with cupping is also a feature in several bone dysplasias, especially those with prominent metaphyseal involvement,including metaphyseal chondrodysplasias (Jansen, OMIM 156400; McKusick, OMIM 250250; Schmid, OMIM 156500;

Ada Deficiency Scid
Fig. 2.29. Vitamin D-resistant rickets in a 13-month-old girl. The anterior rib ends are flared and cupped

Shwachman-Diamond, OMIM 260400; Spahr, OMIM 250400; adenosine deaminase (ADA) deficiency, OMIM 102700; acroscyphodysplasia, OMIM 250215; metaphyseal anadysplasia, OMIM 309645), achondro-genesis (types I and II, OMIM 200600, 200610, 200700), achondroplasia (OMIM 100800), asphyxiating thoracic dysplasia (OMIM 208500), thanatophoric dysplasia (OMIM 187601, 187601), short rib-poly-dactyly syndromes (OMIM 263530, 263520, 253510), and hypophosphatasia (OMIM 241500, 146300). Severe combined immunodeficiency (SCID) with adenosine deaminase (ADA) deficiency and chondro-osseous dysplasia (OMIM 102700) is an autosomal recessive disorder of both cellular and humoral immu-nity,which is often fatal within the 2nd year of life owing to recurrent infections, failure to thrive, and very low levels of ADA activity in peripheral blood mononuclear cells, erythrocytes, lymphocytes and fi-broblasts. Radiologic manifestations are those of a metaphyseal dysplasia, with irregular, splayed meta-physes of the long bones, bony spurs at the metaphy-seal edges, short, wide ribs with cupped ends,'bone-within-bone' appearance of the vertebrae, central beaking of lower thoracic vertebrae, mild platyspondyly, squared-off iliac wings, flat acetabula, irregular iliac crests, and narrow sciatic notch. On frontal chest films the thymic shadow is absent (Cederbaum et al. 1976; Lallemand et al. 1979). Hy-pophosphatasia is a heterogeneous disorder in which the onset of symptoms may occur at birth (congenital form), within the first 6 months (infantile form), in early childhood (childhood form), or in adulthood (adult form). Deficiency of tissue (bone, liver, kidney) and serum alkaline phosphatase and excessive urinary excretion of phosphoethanolamine are common to all types (Jones 1997). Hypophosphatasia, congeni tal lethal form (OMIM 241500), is a perinatally lethal condition of autosomal recessive inheritance (gene mapped to 1p36.1-p34). The direct cause of death is respiratory distress or intracranial hemorrhage. Radiographic manifestations are dominated by the severe lack or absence of bone ossification. The calvarium is poorly mineralized or totally unossified. The long bones are severely short, fragile, with irregular meta-physeal ossification defects extending into the dia-physes; the ulnas and fibulas are often ossified only in their proximal portions, ending in the characteristic 'spur' shape at their midshaft. Entire bones, especially the short tubular bones,may be missing. The thoracic cage is small, with short, thin ribs and unossified ends. The ossification defect also involves the vertebrae, most notably in the neural arches. The scapulae and pelvic bones are small, with large marginal ossification defects (Shohat et al. 1991). Hypophosphatasia tarda (OMIM 146300) manifesting in the first few months of life (infantile form) is characterized by growth deficiency, episodic vomiting, rachitic rosary, increased intracranial pressure and wide cranial sutures, recurrent respiratory infections, and early death in about 50% of cases. Radiological manifestations include delayed ossification of the calvarium and skull base, large metaphyseal ossification defects in the long bones and ribs, and angulation of the long bones (Fig. 2.30). The inheritance pattern is autosomal recessive, most patients being compound heterozygotes for a number of different mutations (in each allele of the gene).When the disease manifests in childhood,major symptoms include premature shedding of deciduous teeth,rickets-like changes in the skeleton (rosary, bowing of long bones, gait disturbances), recurrent fractures, and - in some cases - premature closure of the cranial sutures resulting in craniostenosis. Changes in the metaphyses of the long bones and ribs are similar to those of the infantile form. The adult form is characterized by premature loss of adult teeth, osteoporosis, pseudofractures, bowing of the long bones, cran-iostenosis (inconstant, as in childhood), ectopic calcifications of the vertebral ligaments and disks, articular chondrocalcinosis, and nephrocalcinosis (Fallon et al. 1984). Mild forms of the disease can be difficult to recognize in adulthood, since they become manifest only with increased bone fragility, premature loss of teeth, joint stiffness and pain, and minimal gait difficulties. Severe cases with hypophosphatasia tarda may be indistinguishable from mild cases of the congenital lethal form. Differentiation between hypophosphata-sia and rickets relies on the presence in hypophos-phatasia of large skeletal ossification defects, as well as on laboratory findings (increased serum alkaline

Kyphomelic Dysplasia

Fig. 2.30. Hypophosphatasia, infantile form in a 2-day-old neonate. The anterior rib ends are cupped, with irregular ossification defects. The ribs are short and thin, resulting in a small thorax. The vertebrae in this case are relatively well ossified, which is a point of difference from the lethal form

Fig. 2.30. Hypophosphatasia, infantile form in a 2-day-old neonate. The anterior rib ends are cupped, with irregular ossification defects. The ribs are short and thin, resulting in a small thorax. The vertebrae in this case are relatively well ossified, which is a point of difference from the lethal form phosphatase activity in rickets; decreased or absent serum alkaline phosphatase activity and high urinary excretion of phosphoethanolamine in hypophos-phatasia).

Thin and short ribs with cupped ends are found in fibrochondrogenesis (OMIM 228520), together with short, dumbbell-shaped long bones with flared meta-physes, platyspondyly with superior-inferior clefting defects, and small pelvis, with rounded lateral borders and small sacrosciatic notches (Eteson et al. 1984). In kyphomelic dysplasia (OMIM 211350) flaring is seen at the costochondral ends of the ribs and at the meta-physes of long bones (Temple et al. 1989). The ribs are also moderately short, resulting in a narrow thorax.

Although widening of the lateral and anterior portions of the ribs, coupled with posterior constriction (oar-like or paddle-like shape), is a consistent finding in patients with mucopolysaccharidosis type I-H (Hurler) and type IV (Morquio) and mucolipidosis II

and III, this phenotype is clearly distinct from that described in this section.

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Responses

  • Ralph
    What Causes Flared Ribs?
    5 years ago
  • orlando
    Where is the metaphyseal region in ribs?
    4 years ago
  • Stuart
    What causes rib flaring?
    4 years ago
  • federica
    What is rib flareing and cupping ribs?
    3 years ago

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