The curvatures are cervical, thoracic, lumbar, pelvic (= sacral). Each vertebra has centrum and neural arch in which the latter encloses a neural canal for spinal cord. Between the centra of adjacent vertebrae there are elastic pads of fibro cartilage, the intervertebral discs which provide mobility to the vertebrae, check undue friction and take up shocks.
Displacement of the vertebrae from its normal position due to displacement or degeneration of a part of intervertebral disc is called slip disc.
Possess reduced heads of cervical ribs. All cervical vertebrae except 7th possess vertebrarterial canals for the passage of cervical blood vessels and nerves. 1st cervical vertebrae are ATLAS without having centrum. It is articulated to skull through occipital condyles for nodding movements. Zygopophyses are absent.
IInd cervical vertebra is AXIS. It contains odontoid process that fits into the odontoid canal of atlas to provide head with sideways rotation.
Ribs of 1st nine thoracic vertebrae are long and ventrally articulated with breast bone and remaining vertebrae has floating ribs. This shows that these vertebrae have the regions for attachment of ribs.
These vertebrae are largest, heaviest and strongest as they bear weight of the abdominal viscera. Anterior lumber (first two) bears a median ventral process of centrum called hypopophysis. These vertebrae possess additional processes like metapophysis and anapophysis.
First five sacral vertebras fused to form sacrum. It is a strong and short supporting pelvic girdle as it (sacrum) articulates with the ilium of pelvic girdle.
Mainly 3 to 4 caudal vertebrae fused to form small triangular bone called coccyx. It is a vestigial tail.