Tojima S, Yamada S. Classification of the "human tail": Correlation between position, associated anomalies, and causes.
Clin Anat 2020;
33:929-942. [PMID:
32319695 DOI:
10.1002/ca.23609]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/15/2020] [Accepted: 04/18/2020] [Indexed: 11/08/2022]
Abstract
INTRODUCTION
Numerous case reports have indicated that the "human tail" is not always a harmless protrusion but can be associated with anomalies such as occult dysraphic malformations. However, the definition and classification of this anomaly have not been discussed. A prevailing hypothesis is that the "human tail" is a residual embryonic tail. Herein, we attempted to classify and define the human tail and investigate the frequency of this anomaly.
MATERIALS AND METHODS
We first defined the human tail as a protrusion on the dorsal side of the lumbar, sacrococcygeal, and para-anal regions identified after birth. We collected case reports written in English, Japanese, French, German, and Italian that were published from the 1880s to the present.
RESULTS
We discovered two important findings: (a) the cause of this anomaly may differ even though the "tails" resemble each other closely in appearance and (b) its position tends to be correlated with the type of anomaly and its associated cause. We propose a new classification of the human tail based on these findings.
CONCLUSION
Our classification may facilitate more accurate treatment and precise case descriptions of the human tail.
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