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A typical vertebra has a body (vertebral body), also known as the centrumwhich consists of a large anterior middle portion, and a posterior vertebral arch, [2] also called a neural arch. [3] The body is composed of cancellous bone, which is the spongy type of osseous tissue, whose microanatomy has been specifically studied within the pedicle ...
It is used in both gross anatomy and microscopic anatomy to describe structures. Some examples include: The laminae of the thyroid cartilage: two leaf-like plates of cartilage that make up the walls of the structure. [2] The vertebral laminae: plates of bone that form the posterior walls of each vertebra, enclosing the spinal cord. [3]
The laminae are broad, thick, and imbricated – that is to say, they overlap those of subjacent vertebrae like tiles on a roof and connect with the pedicles to surround and protect the spinal cord. The intervertebral foramen is small, and circular, with two at each intervertebral level, one for the right and one for the left exiting nerve roots.
In human anatomy, the five vertebrae are between the rib cage and the pelvis.They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process (since it is only found in the cervical region) and by the absence of facets on the sides of the body (as found only in the thoracic region).
They are attached to the body of the first sacral vertebra and to each ala, by short thick pedicles; on the upper surface of each pedicle is a vertebral notch, which forms the lower part of the foramen between the last lumbar and first sacral vertebrae. The apex is directed downward and presents an oval facet for articulation with the coccyx.
The pedicles are directed laterally and backward, and attach to the body midway between its upper and lower borders, so that the superior vertebral notch is as deep as the inferior, but it is, at the same time, narrower. The laminae are narrow and thinner above than below; the vertebral foramen is large and of a triangular form.
Articular processes spring from the junctions of the pedicles and laminæ, and there are two right and left, and two superior and inferior. These stick out of an end of a vertebra to lock with a zygapophysis on the next vertebra, to make the backbone more stable.
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.