thoracic vertebrae

Information about thoracic vertebrae

Bone:
A typical thoracic vertebra
Transverse section through the upper margin of the second thoracic vertebra.
Latinvertebrae thoracales
subject #22 102
MeSH Thoracic+Vertebrae
The thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. They are intermediate in size between those of the cervical and lumbar regions; they increase in size as one proceeds down the spine, the upper vertebrae being much smaller than those in the lower part of the region. They are distinguished by the presence of facets on the sides of the bodies for articulation with the heads of the ribs, and facets on the transverse processes of all, except the eleventh and twelfth, for articulation with the tubercles of the ribs.

General characteristics

These are the general characteristics of the second through eighth thoracic vertebrae. The first and ninth through twelfth vertebrae contain certain peculiarities, and are detailed below.

The bodies in the middle of the thoracic region are heart-shaped, and as broad in the antero-posterior as in the transverse direction.

At the ends of the thoracic region they resemble respectively those of the cervical and lumbar vertebrae.

They are slightly thicker behind than in front, flat above and below, convex from side to side in front, deeply concave behind, and slightly constricted laterally and in front.

They present, on either side, two costal demi-facets, one above, near the root of the pedicle, the other below, in front of the inferior vertebral notch; these are covered with cartilage in the fresh state, and, when the vertebrae are articulated with one another, form, with the intervening intervertebral fibrocartilages, oval surfaces for the reception of the heads of the ribs.

The pedicles are directed backward and slightly upward, and the inferior vertebral notches are of large size, and deeper than in any other region of the vertebral column.

The laminae are broad, thick, and imbricated — that is to say, they overlap those of subjacent vertebrae like tiles on a roof.

The vertebral foramen is small, and of a circular form.

The spinous process is long, triangular on coronal section, directed obliquely downward, and ends in a tuberculated extremity.

These processes overlap from the fifth to the eighth, but are less oblique in direction above and below.

The superior articular processes are thin plates of bone projecting upward from the junctions of the pedicles and laminae; their articular facets are practically flat, and are directed backward and a little lateralward and upward.

The inferior articular processes are fused to a considerable extent with the laminae, and project but slightly beyond their lower borders; their facets are directed forward and a little medialward and downward.

The transverse processes arise from the arch behind the superior articular processes and pedicles; they are thick, strong, and of considerable length, directed obliquely backward and lateralward, and each ends in a clubbed extremity, on the front of which is a small, concave surface, for articulation with the tubercle of a rib. *

Peculiar thoracic vertebrae

Enlarge picture
The first and ninth through twelfth thoracic vertebra have some peculiarities

First thoracic vertebra

The first thoracic vertebra has, on either side of the body, an entire articular facet for the head of the first rib, and a demi-facet for the upper half of the head of the second rib.

The body is like that of a cervical vertebra, being broad transversely; its upper surface is concave, and lipped on either side.

The superior articular surfaces are directed upward and backward; the spinous process is thick, long, and almost horizontal.

The transverse processes are long, and the upper vertebral notches are deeper than those of the other thoracic vertebrae.

Ninth thoracic vertebra

The ninth thoracic vertebra may have no demi-facets below. In some subjects however, it has two demi-facets on either side; when this occurs the tenth has only demi-facets at the upper part.

Tenth thoracic vertebra

The tenth thoracic vertebra has (except in the cases just mentioned) an entire articular facet on either side, which is placed partly on the lateral surface of the pedicle.

Eleventh thoracic vertebrae

In the eleventh thoracic vertebrae the body approaches in its form and size to that of the lumbar vertebrae.

The articular facets for the heads of the ribs are of large size, and placed chiefly on the pedicles, which are thicker and stronger in this and the next vertebrae than in any other part of the thoracic region.

The spinous process is short, and nearly horizontal in direction.

The transverse processes are very short, tuberculated at their extremities, and have no articular facets.

Twelfth thoracic vertebra

The twelfth thoracic vertebra has the same general characteristics as the eleventh, but may be distinguished from it by its inferior articular surfaces being convex and directed lateralward, like those of the lumbar vertebrae; by the general form of the body, laminae, and spinous process, in which it resembles the lumbar vertebrae; and by each transverse process being subdivided into three elevations, the superior, inferior, and lateral tubercles: the superior and inferior correspond to the mammillary and accessory processes of the lumbar vertebrae. Traces of similar elevations are found on the transverse processes of the tenth and eleventh thoracic vertebrae.

Additional images


Vertebral column.

Vertebral column.

Vertebral arches of three thoracic vertebræ viewed from the front.

Section of the costotransverse joints from the third to the ninth inclusive.


References

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

See also

External links


Spine [ edit]
general structures: body of vertebra, vertebral arch (pedicle, lamina, vertebral notch), foramina (vertebral, intervertebral), processes (transverse, articular, spinous) cervical vertebrae: C1 (anterior arch, posterior arch, lateral mass), C2 (dens), C7, posterior tubercle, foramen transversarium thoracic vertebrae: costal facets (superior, inferior, transverse) lumbar vertebrae: accessory process, mammillary process sacrum/coccyx: pelvic surface (anterior sacral foramina, dorsal surface (posterior sacral foramina, median sacral crest, medial sacral crest, lateral sacral crest), lateral surface, base, sacral hiatus
Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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vertebral column (backbone or spine) is a column of 34 vertebrae, the sacrum, intervertebral discs, and the coccyx situated in the dorsal aspect of the torso, separated by spinal discs. It houses the spinal cord in its spinal canal.
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In vertebrates, cervical vertebrae (singular: vertebra) are those vertebrae immediately behind (caudal to) the skull.

Variation among species

In some species, some parts of the skull may be composed of vertebra-like elements, e.g.
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The lumbar vertebrae are the largest segments of the movable part of the vertebral column, and are characterized by the absence of the foramen transversarium within the transverse process, and by the absence of facets on the sides of the body.
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RIB can mean:
  • Rigid-hulled inflatable boat
  • Romanian International Bank
  • Routing Information Base
This article is about the bones called ribs. For other meanings, see rib (disambiguation).

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In anatomy, a foramen is any opening.

Examples

Skull

See Foramina of skull

Other

  • the apical foramen is the hole at the tip of the root of a tooth.
  • the foramen ovale (heart) is a hole between the venous and arterial sides of the fetal heart.

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Public domain comprises the body of knowledge and innovation (especially creative works such as writing, art, music, and inventions) in relation to which no person or other legal entity can establish or maintain proprietary interests within a particular legal jurisdiction.
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Henry Gray's Anatomy of the Human Body (or Gray's Anatomy as it has commonly been shortened) is an English-language human anatomy textbook widely regarded as a classic work on the subject.
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Costovertebral articulations -- The articulations of the ribs with the vertebral column may be divided into two sets:
  • Articulation of head of rib -- connecting the heads of the ribs with the bodies of the vertebrae.

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Georgetown University is a private, Jesuit, research university, located in Washington, D.C.'s Georgetown neighborhood. Father John Carroll founded the school in 1789, though its roots extend back to 1634.
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vertebral column (backbone or spine) is a column of 34 vertebrae, the sacrum, intervertebral discs, and the coccyx situated in the dorsal aspect of the torso, separated by spinal discs. It houses the spinal cord in its spinal canal.
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The body is the largest part of a vertebra, and is more or less cylindrical in shape.

Its upper and lower surfaces are flattened and rough, and give attachment to the intervertebral fibrocartilages, and each presents a rim around its circumference.
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The vertebral arch (or neural arch) is the posterior part of a vertebra.

It consists of a pair of pedicles and a pair of laminae, and supports seven processes:
  • four articular processes
  • two transverse processes
  • one spinous process


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The pedicles (from Latin pediculus, "small foot") are two short, thick processes, which project backward, one on either side, from the upper part of the body, at the junction of its posterior and lateral surfaces.
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The laminæ are two broad plates directed backward and medially from the pedicles.

They fuse in the middle line posteriorly, and so complete the posterior boundary of the vertebral foramen.
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Spine [ edit]
general structures: body of vertebra, vertebral arch (pedicle, lamina, vertebral notch), foramina (vertebral, intervertebral), processes (transverse, articular, spinous) cervical vertebrae:
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In a typical vertebra, the vertebral foramen is the foramen formed by the anterior segment (the body), and the posterior part, the vertebral arch.

The vertebral foramen begins at cervical vertebrae #1 (atlas) and continues inferior to lumbar vertebrae #5.
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intervertebral foramina (singular: foramen; also called neural foramina). The foramen allows for the passage of the spinal nerve root, dorsal root ganglion, the spinal artery of the segmental artery, communicating veins between the internal and external plexuses,
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The transverse processes of a vertebra, two in number, project one at either side from the point where the lamina joins the pedicle, between the superior and inferior articular processes. They serve for the attachment of muscles and ligaments.
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The articular processes (zygapophyses) of a vertebra, two superior and two inferior, spring from the junctions of the pedicles and laminæ.
  • The superior processes project upward from a lower vertebra, and their articular surfaces are directed more or less backward.

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The spinous process of a vertebra is directed backward and downward from the junction of the laminae (in humans), and serves for the attachment of muscles and ligaments. In animals without an erect stance, the process points upward and may slant forward or backward.
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In vertebrates, cervical vertebrae (singular: vertebra) are those vertebrae immediately behind (caudal to) the skull.

Variation among species

In some species, some parts of the skull may be composed of vertebra-like elements, e.g.
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In anatomy, the atlas (C1) is the topmost (first) cervical vertebra of the spine.

It is named for the Atlas of mythology, because it supports the globe of the head.
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The anterior arch of the atlas forms about one-fifth of the ring of the atlas: its anterior surface is convex, and presents at its center the anterior tubercle for the attachment of the Longus colli muscles; posteriorly it is concave, and marked by a smooth, oval or circular facet
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In a cervical vertebra, the posterior arch forms about two-fifths of the circumference of the ring: it ends behind in the posterior tubercle, which is the rudiment of a spinous process and gives origin to the Recti capitis posteriores minores.
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The lateral masses are the most bulky and solid parts of the atlas, in order to support the weight of the head.

Each carries two articular facets, a superior and an inferior.
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axis (from Latin axis, "axle") or epistropheus.

It forms the pivot upon which the first cervical vertebra (the atlas), which carries the head, rotates.
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The dens or odontoid process or odontoid peg of the axis exhibits a slight constriction or neck, where it joins the body.

On its anterior surface is an oval or nearly circular facet for articulation with that on the anterior arch of the atlas.
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Vertebra prominens is the proper name for the seventh cervical vertebra. The most distinctive characteristic of this vertebra is the existence of a long and prominent spinous process which is papable from the skin surface, hence the name.
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