Vertebral columnThe vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordates has been replaced by a segmented series of bone: vertebrae separated by intervertebral discs. Individual vertebrae are named according to their region and position, and can be used as anatomical landmarks in order to guide procedures such as lumbar punctures.
VertebraThe spinal column, a defining synapomorphy shared by nearly all vertebrates, is a moderately flexible series of vertebrae (: 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.
Atlas (anatomy)In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck. The bone is named for Atlas of Greek mythology, for just as Atlas bore the weight of the heavens, the first cervical vertebra supports the head. However, the term atlas was first used by the ancient Romans for the seventh cervical vertebra (C7) due its suitability for supporting burdens. In Greek mythology, Atlas was condemned to bear the weight of the heavens as punishment for rebelling against Zeus.
Cervical vertebraeIn tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid species, the cervical vertebrae bear cervical ribs. In lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The vertebral transverse processes of mammals are homologous to the cervical ribs of other amniotes.
Spinal cordThe spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spinal cord, which contains cerebrospinal fluid. The brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone, passing through the foramen magnum and then enters the spinal canal at the beginning of the cervical vertebrae.
LordosisLordosis is historically defined as an abnormal inward curvature of the lumbar spine. However, the terms lordosis and lordotic are also used to refer to the normal inward curvature of the lumbar and cervical regions of the human spine. Similarly, kyphosis historically refers to abnormal convex curvature of the spine. The normal outward (convex) curvature in the thoracic and sacral regions is also termed kyphosis or kyphotic. The term comes from the Greek lordōsis, from lordos ("bent backward").
RibIn vertebrate anatomy, ribs (costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax. In some animals, especially snakes, ribs may provide support and protection for the entire body. Human ribs are flat bones that form part of the rib cage to help protect internal organs.
ScoliosisScoliosis (: scolioses) is a condition in which a person's spine has a sideways curve. The curve is usually "S"- or "C"-shaped over three dimensions. In some, the degree of curve is stable, while in others, it increases over time. Mild scoliosis does not typically cause problems, but more severe cases can affect breathing and movement. Pain is usually present in adults, and can worsen with age. As the condition progresses, it may impact a person's life and hence, can also be considered a disability.
ThoraxThe thorax (: thoraces or thoraxes) or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the creature's body, each of which is in turn composed of multiple segments. The human thorax includes the thoracic cavity and the thoracic wall. It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures.
Axis (anatomy)In anatomy, the axis (from Latin axis, "axle") or epistropheus is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The axis' defining feature is its strong odontoid process (bony protrusion) known as the dens, which rises dorsally from the rest of the bone. The body is deeper in front or in the back and is prolonged downward anteriorly to overlap the upper and front part of the third vertebra.
