The average person is born with 33 individual bones. By the time an individual becomes an adult, most of the individuals are left with only 24 vertebrae, as during normal growth and development, some vertebrae at the lower end of the spine get fused together.A sacrum is considered the bottom of the spine. It is composed of multiple vertebral bodies that are normally united as one. The remaining tiny bones or ossicles are also fused together below the sacrum and are called the tailbone or coccyx. Above the sacrum, the spine consists of:In the body, seven bones - the cervical spine. In the chest, 12 bones - the thoracic spine. In the lower back, five bones - the lumbar spine.