Vertebra Superior View-en.svg
A typical vertebra, superior view
Vertebra Posterolateral-en.svg
A section of the human vertebral column, showing multiple vertebrae in a left posterolateral view.
Part ofSpinal column
Anatomical terms of bone

The spinal column, a defining synapomorphy shared by nearly all vertebrates,[Note 1] is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the backbone), and on the other with phylogenetic differences among the vertebrate taxa.

The basic configuration of a vertebra varies, but the bone is its body, with the central part of the body constituting the centrum. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch (in eleven parts, consisting of

  • two pedicles (pedicle of vertebral arch)
  • two laminae, and
  • seven processes.

The laminae give attachment to the ligamenta flava, which are ligaments of the spine. There are vertebral notches, each constituted by the shape of the pedicles, which form the intervertebral foramina when [1] vertebrae articulate. These foramina are the entry and exit conduits accommodating the spinal nerves. The body of the vertebra, and its vertebral arch, form the vertebral foramen, which is the larger, stable and central opening: this accommodates the spinal canal, and encloses and protects the spinal cord.

Vertebrae articulate with each other to give strength and flexibility to the spinal column, and the shape at their back and front aspects determines the range of movement. Structurally, vertebrae are essentially alike across the vertebrate species, with the greatest difference seen between an aquatic animal and other vertebrate animals. As such, vertebrates take their name from the vertebrae that compose the vertebral column.

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