Do Humans really have a Vestigial Tailbone? If not then what is it?

Many people make the claim that Man has a "tailbone" left over from evolution.

This page will examine these claims and show that mans "tailbone" is nothing of the sort... and rather than being a left over from evolution, the "tailbone" has a distinct role and purpose.

The following is an excert from:

'Vestigial Organs' are Fully Functional"
By Dr. Jerry Bergman & Dr. George Howe

(* I have recieved permission to reprint this information)


The Coccyx Defined as a Supposed Vestige

Humans differ from most primates in that they lack a tail. The lower primates have tails, and the apes, which are believed by many to be our closest relatives, likewise are tailless. The human coccyx (also called the os coccyx) was viewed by Drummond (1903) as a rudimentary tail left over from our distant past and therefore vestigial. The coccyx bones were interpreted as remnants of a structure which strongly linked humans to the lower primates.

Both D. Morris (1985) and Pansky (1975) saw the coccyx as all that yet remains of our primate tail. Cartmill et al. (1987:186) asserted that the coccygeus muscle and sacrospinous ligament which attach to the coccyx are vestiges of a “. . . powerful muscle that acts to tuck the tail down in a dog’s body:’ Pinchot (1985:41) claimed that the coccyx is the only part of the skeleton without a function. The coccyx and associated structures were and still are beleved to be useless remnants of evolution.

The coccyx is composed of three to five (usually four) nodular pieces of fused vertebral bones at the lowest part of the vertebral column. There is some evidence that the coccyx in modern humans is one vertebra longer than it was in Neanderthals; but this difference may be merely a racial variation.

Contributions of The Coccyx
The coccyx is triangular in shape and attached to the bottom of the sacrum. Its name “coccyx” means cuckoo; it was named because of its resemblance to a cuckoo’s bill—see Walker (1987:253). Because it is not connected to the ribs, the coccyx does not have pedicles, lamina, or spinous processes that are present on certain other vertebrae. The coccygeal vertebrae have only three transverse grooves which provide an attachment to the ventral sacrococcygeal ligaments and the levatores aid, two broad thin muscles which form part of the hammock-like floor of the pelvis. These muscles function as a single sheet which extends across the middle line, forming the principal part of the pelvic diaphragm and support for the rectum. The coccygeus muscle also helps to support the posterior organs of the pelvic floor, especially during blocked forced expiration, as in elimination.

The coccygeus muscle can draw the coccyx ventrally to give added support to the pelvic floor against abdominal pressure. It draws the coccyx forward after defecation. This muscle is inserted by its base into the margin of the coccyx and into the side of the last section of the sacrum. The coccygeus muscle consists of the levator aid and the prirformis which enclose the back part of the outlet of the pelvis.

In females, the coccygeus muscle draws the coccyx forward after it has been pressed back during parturition. Smith (1986:134) reported that the movements of the coccyx help to enlarge the birth canal during childbirth. The levator ani muscles constrict the lower end of both the rectum and the vagina, drawing the rectum both forward and upward- see Anthony (1963:411). Far from being remnants of muscles that pull the tail down in a dog, as Cartmill et al. (1987:186) and others claim, the small sling of muscles attached to the coccyx serves several functions.

On the left and right dorsal surfaces of the coccyx is located a row of tubercles called the “rudimentary articular processes" However, they are “rudimentary” only in the sense that they are smaller than the tubercies on the thoracic vertebrae. The larger first pair, the coccygeal cornua, articulate with the cornua of the sacrum and allow some movement. On the oppsite side are the openings called foramina-openings for the transmission of the dorsal division of the fifth sacral nerve. The narrow borders of the coccyx receive the attachment of the sacrotuberous and sacrospinous ligaments laterally for support of the bones, the coccygeus muscle ventraIly, and the gluteus maximus muscle dorsally

The oval surface of the coccyx base articulates with the sacrum. Cray (1966:130) pointed out that the rounded apex or lowest part of the coccyx is attached to the tendon of the sphincter ani externus and its movement can be bifid, meaning that it can be deflected to both sides, and thus make bowel movements possible. Also, Cray (1966: 130) discussed the anococ-cygeal raphe which is a narrow fibrous band that extends from the coccyx to the margin of the anus.

Citing an anatomy textbook, Scadding (1981) concluded this very succinctly by stating that several muscles and ligaments insert on the coccyx. Walker (1987:253) noted that it is the coccyx ”... to which certain anal and perineal muscles attach:’ Weischnitzer (1978: 285) reported that the iliococcygeus muscle “. . . supports and raises the pelvic floor’ He indicated that the iliococcygeus is inserted on terminal parts of the coccyx.

Without the coccyx and its attached muscle system, humans would need a radically different support system for their internal organs which would require numerous design changes in the human posterior Concerning the coccyx and its importance, Allford concluded that:

"The posterior surfaces [of the coccyx] serve as attachments for the gluteus maximus muscle and the sphincter and externus muscles. The gluteus maximus muscle is essential for defecation and labor during childbirth. The sphincter ani externus muscle is needed to keep the anal canal and orifice closed. These are obviously very important functions. The interior surfaces of the coccygeal vertebrae also serve as important attachments for muscles that aid in the containment of feces within the rectum . . . [as well as control of] defecation, and the expulsion of the fetus during labor. For these important reasons, the coccyx can never be classified as a rudimentary or vestigial rudiment of our ancestors. Aliford (1978:42)

Franks dealt with coccyx malfunction as follows:

"Individuals who injure the tailbone may develop a painful condition called coccydynia. Removal of the coccyx presumably because it is thought to be nonessential seems to be a poor operation. I counsel my patients with tailbone pain to resist removal of the coccyx if ever suggested" . Franks (1988:24)

The coccyx is not the only support system of the internal organs; the diaphragm and other muscles also help fulfill this role. If the coccyx is surgically removed, enough surrounding supporting structures exist in adults so one can live fairly normally. The three to five small bones are obviously part of a larger support structure consisting of bones, cartilage, muscle, ligaments, and tendons, all of which participate.

Concerning surgery of the coccyx, Shute noted that the vestigial organ argument is not realistic:

Take it away and patients complain; indeed the operation for its removal has time and again fallen into disrepute, only to be revived by some naive surgeon who really believes what the biologists have told him about this useless ‘rudiment: Shute (1961:40)

Reno argued that the coccyx need not be classed as a useless remnant of evolution. Her practical words illustrate the fact that the coccyx was often judged vestigial merely because of its position “The coccyx . . . is merely the terminal portion of the backbone. After all, it does have to have an end!” Reno (1970:81)

Does The Human Embryo Have A Tail?

Asimov asserted that man’s embryo has a tail:

If there is any doubt that the coccyx represents a tail and not something else entirely, the answer lies in the study of the developing human embryo. In the early stages a small but distinct tail region is formed. By the eighth week of development it is gone, but its evanescent existence would seem to make it clear, that man descended from some creature with a tail, and that he still carries about with him, hidden below the skin, a last evidence of it. Asimov (1963:39)

Some years later Smith took a different view of the human embryonic “tail”:

"....although the human embryo has a short stub of a tail for a while and this is precisely similar to the short stubs that become tails in many other species, the human tail stub only forms the basis of the human coccyx. Mankind does not travel up the trunk of the animal tree with each embryo. . ." . Smith (1986:118).

Gould (1982:41) noted that at four weeks humans have a well-formed tail which is larger at that time than their legs. Shute (1961:40) added that although in its development, the human embryo appears tailed this is simply because

"... “. . . there is disproportionate development of various parts of the fetal skeleton:’

Are Some Human Babies Actually Born With A Tail?

At birth some human babies have a short “tail-like” growth called a “caudal appendage;’ located near the inferior end of the spinal column. While documenting the occurrence of such caudal appendages, Ledley stated the evolutionists’ bold claim about the supposed relationship of the caudal appendage to human origins:

"There is something seemingly unhuman about the presence on a human infant of a ‘tail’ like the tails found on other primates. It is incongruous; it violates our sense of anthropocentricity, and it raises issues that involve not only teratology and embryology but also our view of ourselves and our place in evolution.

To evolutionists the ‘human tail’ was an example of a ‘reversion to a lower species’ and an illustration of the doctrine that ‘ontogeny recapitulates phylogeny

The human tail serves as an example of modern concepts of ontogeny and phylogeny and presents a striking clinical confrontation with the reality of evolution.

Even those who are familiar with the literature that defined our place in nature-from Darwin’s The Descent of Man to Wilson’s On Human Nature-are rarely confronted with the relation between human beings and their primitive ancestors on a daily basis. The caudal appendage brings this reality to the fore and makes it tangible and inescapable. Ledley (1982:1212, 1215)

The brief research portion of Ledley’s paper (1982:1212) concerned the case report of a 7-pound baby that was born with a caudal appendage 2 inches in length. Shortly after it was born the child was transferred to Children’s Hospital Medical Center in Boston where doctors removed the growth. Ledley related that it was a “. . . well-formed caudal appendage” located near the end of the baby’s spine; “. . . it was covered by skin of normal texture and had a soft fibrous consistency:’ Ledley also noted that there were no vertebrae or even cartilaginous elements in the so-called “caudal appendage:’ Ledley included a helpful review of caudal appendage research. Such cases have been noted throughout history, but very few have been scientifically documented. The rest of Ledley’s paper consisted of a bold defense of macroevolution involving ontogeny and comparative embryology.

We do not intend to discuss the evolutionary concept that an individual retraces his evolution during his embryological development; viz., “on-togeny recapitulates phylogeny’ It will be sufficient to note that some embryologists have totally rejected this idea as an appealing but naive and mistaken view of embryogenesis:

I wonder whether the phrase ‘ontogeny recapitulates phylogeny would so persistently have fascinated biologists, or so long have survived among the debris of half forgotten science that we all retain from high school, if it were not rather euphonious. Would something like ‘development repeats evolutinary history’ have worn so well? K. S. Thomson (1988)

K. S. Thomson (1988) also asserted that the recapitulation concept has little if any meaning in modern biology; he viewed it to be a dead concept. In addition to demonstrating that Haeckel’s paradigm is totally inadequate, Rusch (1969) showed that some of Haeckel’s drawings purporting L. to demonstrate embryonic recapitulation were fraudulent. Even Gould (1982:41), the reviewer of Ledley’s paper, noted that M. “. . . the theory of recapitulation died more than fifty years ago:’ N.

Remine and an anonymous coauthor from the University of Minnesota analyzed Ledley’s findings shortly after the report was published. Their pointed critique of Ledley’s evolutionary thesis speaks for itself:

In evaluating this case report it may be noted firstly that the caudal appendage is not connected to the vertebral column as are the tails of other vertebrates. In addition, the appendage is not even in line with the vertebral column but is 1.5 cm to the right of the midline. Secondly, the appendage contains no bony structures as do the tails of all other vertebrates. These two points support the interpretation that this appendage is not a “true tail” but is likely a dermal (skin) remnant of the fetal ectoderm germ layer located by chance in the caudal region. [ReMine here quoted Ledley to show that these caudal appendages of certain human babies are very different than true tails in other vertebrates.]

Many evolutionists view the appendage as tail-like enough to be interpreted as evidence of man’s primitive evolutionary ancestry. This interpretation has two drawbacks. One drawback is that there are good reasons, as given above, why the appendage may not be interpreted as a true tail. Secondly, there is no well established genetic mechanism to account for the preservation of the structural elements necessary for tail formation in the human genome.

Creationists may view the appendage as a structural variant of developmental origin rather than as a ‘tail: ReMine (1982:8)

Ledley himself (1982) admitted that the so-called caudal appendage may be nothing more than a dermal appendage which by chance occurred in that position. Reno noted that one explanation of these abnormal caudal appendages is that each is merely a birth abnormality:

"Could not this be the result of a deranged process taking place during embryologic development? The normal process is sometimes altered and as a result we see Siamese twins, cleft palates and harelips. No one would argue that these were once normal conditions in a remote ancestor. A "tail" could be such an anomally. Reno (1970:86)

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