It's designed with 5, but they all fuse together into one by birth.
You still have 5 pairs of sacral nerves.
The sacrum is a triangular-shaped bone located at the base of the spine. It consists of five fused vertebrae.
sacrum and coccyx
Sacrum
the sacrum
The vetebrae of the lower back are called lumbar vertebrae. Lower than that, the vertebrae are fused together in the sacrum, and the lowest part of the spine is the tailbone or coccyx.
Almost all humans are born with 33 separate vertebrae. By adulthood, most have only 24. This is due to the fusion of the vertebrae in certain parts of the spine during normal development. Different textbooks give different answers to this question. The confusion comes from the fact that the two lowest vertebrae -- the sacrum and the coccyx -- are each one bone, but they are made up from smaller bones fused together. There are 24 separate vertebrae; then there is the sacrum, which is formed from 5 fused vertebrae; and finally the coccyx, which is formed from between 3-5 fused vertebrae. Therefore, if the coccyx and sacrum are each classed as one vertebra, then there are 26 vertebrae. If the fused vertebrae are all counted separately, then there are 32-34 vertebrae.
sacrum and coccyx
Lumbar
the sacrum-bg
Sacrum
the sacrum-bg
sacral hiatus
Sacrum
No. There are no intervertebral discs in the Sacrum. The Sacrum is a fusion between 5 vertebrae and this the same with the Coccyx (fusion of 3). The final intervertebral disc is between L5 and the superior surface of the Sacrum.
coccyx
coccyx
coccyx
Vertebrae are divided into sections: the atlas and axis account for the first cervical vertebrae, of which there are 7 in total; there are 12 thoracic vertebrae, 7 lumbar vertebrae, 1 sacrum (5 separate vertebrae in a baby), and 1 coccyx (4 separate vertebrae in a baby).