Newborn babies born with tails

Newborn babies born with tails - Newborn babies born with...

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Newborn babies born with tails Primarily due to intense medical interest, humans are one of the best characterized species and many developmental anomalies are known. There are several human atavisms that reflect our common genetic heritage with other mammals. One of the most striking is the existence of the rare "true human tail" (also variously known as "coccygeal process", "coccygeal projection", "caudal appendage", and "vestigial tail"). More than 100 cases of human tails have been reported in the medical literature. Less than one third of the well-documented cases are what are medically known as "pseudo-tails" (Dao and Netsky 1984 ; Dubrow et al . 1988 ). Pseudo-tails are not true tails; they are simply lesions of various types coincidentally found in the caudal region of newborns, often associated with the spinal column, coccyx, and various malformations. In contrast, the true atavistic tail of humans results from incomplete regression of the most distal end of the normal embryonic tail found in the developing human fetus (see Figure 2.4.1 and the discussion below on the development of the normal human embryonic tail; Belzberg et al . 1991 ; Dao and Netsky 1984 ; Grange et al . 2001 ; Keith 1921 ). Though formally a malformation, the true human tail is usually benign in nature (Dubrow et al . 1988 ; Spiegelmann et al . 1985 ). The true human tail is characterized by a complex arrangement of adipose and connective tissue, central bundles of longitudinally arranged striated muscle in the core, blood vessels, nerve fibres, nerve ganglion cells, and specialized pressure sensing nerve organs (Vater-Pacini corpuscles). It is covered by normal skin, replete with hair follicles, sweat glands, and sebaceous glands (Dao and Netsky 1984 ; Dubrow et al . 1988 ; Spiegelmann et al . 1985 ). True human tails range in length from about one inch to over 5 inches long (on a newborn baby), and they can move via voluntary striped muscle contractions in response to various emotional states (Baruchin
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Newborn babies born with tails - Newborn babies born with...

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