Tail bone

Tailbone or Coccyx is the final segment of the vertebral column in humans and apes, and certain other mammals such as horses. In humans and other tailless primates (apes) it is the vestigial remnant of a tail, but still not entirely useless; it is an important attachment for various muscles, tendons and ligaments — which makes it necessary for physicians and surgeons to know its anatomy and functions in detail. It also serves as support for a person while in a sitting position.

Anatomy

The coccyx is usually formed of four rudimentary vertebrae; the number may be as high as five or as low as three. It articulates superiorly with the sacrum. In each of the first three segments may be traced a rudimentary body and articular and transverse processes; the last piece (sometimes the third) is a mere nodule of bone. All the segments are destitute of pedicles, laminae, and spinous processes. The first is the largest; it resembles the lowest sacral vertebra, and often exists as a separate piece; the last three diminish in size from above downward.

Clinical significance

Injury to the coccyx is a common cause of coccydynia. The coccyx is also often injured in childbirth. In some extreme cases, the coccyx is removed surgically, a procedure known as a coccygectomy.

History

The term "coccyx" comes from the Greek word for "cuckoo" — it was so named because the curved shape of the coccyx is somewhat like the beak of a cuckoo bird.

See also

• Coccydynia
• Coccygectomy
• Sacrum

References

Tail bone Resources
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