Congenital absence of head, thorax, and abdomen in a parasitic twin with pelvis and legs only. ... (05 Mar 2000) ... 
Type: Term Pronunciation: ā-sef′ă-lō-gas-tēr′ē-ă Definitions: 1. Congenital absence of head, thorax, and abdomen as seen in a parasitic twin with pelvis and lower limbs only.