Significance of Resegmentation in the Pathogenesis of Vertebral Body Malformation

Vertebral Anomaly in Fossil Sea Cows (Mammalia, Sirenia)

“…According to the classifications of Tanaka and Uhthoff ( 1981a, b) and Ghebranious et al (2007), the less developed transverse processes in this study can be explained by error of formation leading to hypoplastic transverse processes. The left–right asymmetry in the vertebrae caused by this failure of formation is confirmed by Erol et al (2002) stating that this may occur on the right or the left side of the body.…”

“…This is supported by Rathke (1952), who states that a constant type of alteration and its restriction to a certain vertebral region argue for a congenital defect. In the studies of Tanaka and Uhthoff (1981a, b) and Erol et al (2002), congenital malformations of the vertebral body were classified into two categories. Type 1 includes failure of formation and Type 2 is a developmental failure of segmentation.…”

The Pathogenesis of Congenital Vertebral Malformations: A Study Based on Observations made in 11 Human Embryos and Fetuses

“…Several authors have commented on the pathogenesis (Feller & Sternberg 1930, Valentin & Putscher 1936, Junghanns 1937, Ehrenhaft 1943, Schmorl & Junghanns 1971, Epstein 1976, and Tsou 1977, but it must be noted that their hypotheses were mostly based on the radiological study of clinical cases or the investigation of older fetuses. Moreover, the interpretation of normal vertebral development on which these theories were based could not be substantiated by recent studies of human embryos (Tanaka & Uhthoff 1981). …”

“…We feel, however, that the distribution of the intersegmental arteries plays a decisive role during the stage of resegmentation and early chondrification, and not during the stage of ossification. Since the intersegmental artery is instrumental in the formation of the definitive vertebral body anlage during the stage of resegmentation (Tanaka & Uhthoff 1981) any abnormal distribution of the arteries may induce malformation.…”

Vertebral ontogenesis: Reseg mentation refuted

“…Eight years ago we supported Remak's (1855) theory of resegmentation (Tanaka and Uhthoff 1981). We can no longer agree with this theory following further review of the subject.…”