Case Report
Thoracopagus Conjoined Twins: A Case Report
Table 1
Embryologic classification of conjoined twins [
2].
| Embryonic aspect | Type | Incidence | Primordium | Extent of union | Separability |
| Ventral (87%) | — | — | — | — | — |
| Rostral (48%) | Cephalopagus | 11% | Oropharyngeal membrane | Top of head to umbilicus | None | Thoracopagus | 19% | Heart | Thorax, upper abdomen, conjoined heart | Rare | Omphalopagus | 18% | Diaphragm | Thorax, upper abdomen, separate hearts | Likely 82% success |
| Caudal (11%) | Ischiopagus | 11% | Cloacal membrane | Lower abdomen, genitourinary tract | Likely 63% success |
| Lateral | Parapagus | 28% | Cloacal membrane (2 notochords?) | Pelvis, variable trunk, diprosopus 2 faces, dicephalus 2 heads | Rare |
| Dorsal (13%) | Craniopagus | 5% | Cranial neuropore | Cranial vault | Unlikely without sequelae | Rachipagus | 2% | Neural tube (mid-portion) | Vertebral column | None reported | Pygopagus | 6% | Caudal neuropore | Sacrum | Likely 68% success |
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