You may not think many human body parts resemble a bird, but think again. The coccyx, the scientific name for tailbone, is derived from the Greek word meaning “cuckoo” because the tailbone resembles the curved shape of a cuckoo’s beak when viewed from the side.
The coccyx is the final segment of the vertebral column in tailless primates. It is comprised of three to five segments, not fused together as previously thought. Contrary to popular belief, it is not entirely useless and is not considered a vestigial structure. The coccyx is an important attachment for various muscles, tendons and ligaments.
– David Martin, VeinInnovations