Aineo wrote:So what you have is a birth defect not unlike other defects that can happen to a human being.
Yes, that developed from the embyonic expression of a tail (see the abstract). Birth defects can be triggered by arrested embryonic development. Here are a few more references:
[The human tail. Report of a case of coccygeal retroposition in childhood] Osservazione di un caso clinico di retroposizione coccigea in eta pediatrica.
Author Falzoni, P; Boldorini, R; Zilioli, M; Sorrentino, G
Affiliation Facolta di Medicina, Universita degli Studi - Novara.
Source Minerva pediatrica, 1995 Nov, 47(11):489-91
The authors explain a little patient's case of coccydynia by back-position of the coccyx; the patient underwent an operation of partial resection with favourable clinical outcome. According to classification, the treated case corresponds to vestigial tail.
and
Human tails have been attributed to a disturbance in fetal tail regression which normally occurs at the gestation age of about 6 weeks. To date, more than 100 cases of human tails have been reported. However, reports of true human tails, which involve the coccygeal vertebrae, are rare. We recently encountered a patient with a true human tail which involved the coccygeal vertebrae and was accompanied by lumbar spinal lipoma and spina bifida. A four-year-old boy was brought to our clinic with complaints primarily of painful mass. The boy had no neurological abnormalities. Physically, a tail bone projected, slightly in the lumbar area, with a linear depression in the center. A hard tail bone was palpable subcutaneously. A soft mass was palpable in the lumbar region, which was accompanied by hemangioma on the superficial layer of the skin in this region. On X-ray films, the tail bone lacked the normal curvature and it projected linearly in the posterior direction. CT scans revealed spina bifida at the level below L2. MRI disclosed spina bifida (at the level below L2), spinal lipoma and a tethered cord. During surgery, the tail bone was first resected over a distance of one and a half vertebral bodies. The lumbar tumor, which continued into the spinal canal, was removed as completely as possible after incision of the dura mater. To free the tethered cord, the tensioned, hypertrophic filum terminale was dissected. Although the morphological diagnosis of this condition is easy, the high incidence of complication by other anomalies makes it essential to perform thorough preoperative examinations with CT and MRI.
from:
MEDLINE
Title [A case of true human tail accompanied with spinal lipoma]
Author Matsuo, T; Koga, H; Moriyama, T; Yamashita, H; Imazato, K; Kondo, M
Affiliation Department of Neurosurgery, Sasebo City General Hospital.
Source No shinkei geka. Neurological surgery, 1993 Oct, 21(10):925-9
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