| Bone: Dens (anatomy) | | | | Second cervical vertebra, or epistropheus, from above. (Dens labeled at center top.) | | | | Second cervical vertebra, epistropheus, or axis, from the side. (Odontoid process labeled at center top.) | | Gray's | subject #21 99 | | Dorlands/Elsevier | d_08/12285795 | The dens or odontoid process or odontoid peg of the axis exhibits a slight constriction or neck, where it joins the body. Image File history File links Gray87. ...
A diagram of a thoracic vertebra. ...
In anatomy, the second cervical vertebra (C2) of the spine is named the axis (from Latin axis, axle) or epistropheus. ...
Image File history File links Gray88. ...
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In anatomy, the second cervical vertebra (C2) of the spine is named the axis or epistropheus. ...
On its anterior surface is an oval or nearly circular facet for articulation with that on the anterior arch of the atlas. 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...
On the back of the neck, and frequently extending on to its lateral surfaces, is a shallow groove for the transverse atlantal ligament which retains the process in position. The transverse ligament of the atlas is a thick, strong band, which arches across the ring of the atlas, and retains the odontoid process in contact with the anterior arch. ...
The apex is pointed, and gives attachment to the apical odontoid ligament; below the apex the process is somewhat enlarged, and presents on either side a rough impression for the attachment of the alar ligament; these ligaments connect the process to the occipital bone. In the triangular interval between the alar ligaments is another fibrous cord, the ligament of apex dentis (or apical odontoid ligament), which extends from the tip of the odontoid process to the anterior margin of the foramen magnum, being intimately blended with the deep portion of the anterior atlantoöccipital...
The alar ligaments connect the sides of the dens (on the axis, or the second cervical vertebra) to tubercles on the medial side of the occipital condyle. ...
The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself. ...
The internal structure of the odontoid process is more compact than that of the body. The odontoid peg is the ascension of the atlas fused to the ascension of the axis. The peg has an articular facet at its front and forms part of a joint with the anterior arch of the atlas. It is a non-weight-bearing joint. The alar ligaments, together with the apical ligaments, are attached from the sloping upper edge of the odontoid peg to the margins of the foramen magnum. The inner ligaments limit rotation of the head and are very strong. The weak apical ligament lies in front of the upper longitudinal bone of the cruciform ligament, and joins the apex of the deltoid peg to the anterior margin of the foramen magnum. It is the fibrous remnant of the notochord.
Dens is also another word for 'teeth', hence the name 'DENTIST'. Fracture Types A type I Fracture extends through the tip of the dens. A type II fracture is through the body and is the most common type. A type III fracture extends through the vertebral body of the vertebra.[1]
Additional images
Articulation between odontoid process and atlas. Image File history File links Gray306. ...
| Median sagittal section through the occipital bone and first three cervical vertebræ. Image File history File links Gray308. ...
| Sagittal section of nose mouth, pharynx, and larynx. Image File history File links Download high resolution version (600x861, 185 KB) Summary See image:Gray994-adenoid. ...
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The University of Michigan, Ann Arbor (UM, U of M or U-M) is a coeducational public research university in the U.S. state of Michigan. ...
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An illustration from the 1918 edition Henry Grays Anatomy of the Human Body (or Grays Anatomy as it has more commonly become known) is an anatomy textbook widely regarded as a classic work on human anatomy. ...
| v • d • e Bones of torso | | sternum: manubrium, body of sternum, xiphoid process, suprasternal notch rib: first rib, tenth rib, eleventh rib, twelfth rib, floating rib, false ribs, angle, tubercle, costal groove, neck, head Grays Anatomy illustration of a human femur. ...
The human torso Torso is an anatomical term for the greater part of the human body without the head and limbs. ...
The sternum (from Greek ÏÏÎÏνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ...
Sternum or breastbone is a long, flat bone located in the center of the thorax (chest). ...
The body of the sternum (gladiolus), considerably lengthier, narrower, and thinner than the manubrium, attains its greatest breadth close to the lower end. ...
The xiphoid process is a small cartilaginous extension to the lower part of the sternum which is usually ossified in the adult human. ...
This article needs to be cleaned up to conform to a higher standard of quality. ...
The human rib cage. ...
The first rib is the most curved and usually the shortest of all the ribs; it is broad and flat, its surfaces looking upward and downward, and its borders inward and outward. ...
The tenth rib has only a single articular facet on its head. ...
The eleventh rib has a single articular facet on the head, which is of rather large size. ...
The twelfth rib has a single articular facet on the head, which is of rather large size. ...
the four floating ribs Four of the ribs (two pairs) in the ribcage are said to be floating ribs because they are attached to the vertebrae only, and not to the sternum or cartilage coming off of the sternum. ...
Excluding the first seven ribs, the remaining five are false ribs. ...
The external surface of the rib is convex, smooth, and marked, a little in front of the tubercle, by a prominent line, directed downward and laterally; this gives attachment to a tendon of the Iliocostalis, and is called the angle. ...
On the posterior surface at the junction of the neck and body of the rib, and nearer the lower than the upper border, is an eminenceâthe tubercle It consists of an articular and a non-articular portion. ...
Between the ridge of the interal surface of the rib and the inferior border is a groove, the costal groove, for the intercostal vessels and intercostal nerve. ...
The neck of the rib is the flattened portion which extends lateralward from the head; it is about 2. ...
The head of the rib is marked by a kidney-shaped articular surface, divided by a horizontal crest into two facets for articulation with the depression formed on the bodies of two adjacent thoracic vertebrae; the upper facet is the smaller; to the crest is attached the interarticular ligament. ...
general vertebral structures: body of vertebra, vertebral arch (pedicle, lamina, vertebral notch), foramina (vertebral, intervertebral), processes (transverse, articular, spinous) The body is the largest part of a vertebra, and is more or less cylindrical in shape. ...
The vertebral arch (or neural arch) is the posterior part of a vertebra. ...
The pedicles 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. ...
The laminæ are two broad plates directed backward and medialward from the pedicles. ...
The concavities above and below the pedicles are named the vertebral notches; and when the vertebrae are articulated, the notches of each contiguous pair of bones form the intervertebral foramina. ...
In a typical vertebra, the vertebral foramen is the foramen formed by the anterior segment (the body), and the posterior part, the vertebral arch. ...
When the spinal vertebrae are articulated with each other the bodies form a strong pillar for the support of the head and trunk, and the vertebral foraminae constitute a canal for the protection of the medulla spinalis (spinal cord). ...
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. ...
The articular processes of a vertebra, two superior and two inferior, spring from the junctions of the pedicles and laminæ. The superior project upward, and their articular surfaces are directed more or less backward; the inferior project downward, and their surfaces look more or less forward. ...
A diagram of a thoracic vertebra. ...
cervical vertebrae: C1 (anterior arch, posterior arch, lateral mass), C2 (dens), C7, anterior tubercle, posterior tubercle, foramen transversarium In vertebrates, cervical vertebrae (singular: vertebra) are those vertebrae immediately behind (caudal to) the skull. ...
In anatomy, the atlas (C1) is the topmost (first) cervical vertebra of the spine. ...
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...
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. ...
The lateral masses are the most bulky and solid parts of the atlas, in order to support the weight of the head. ...
In anatomy, the second cervical vertebra (C2) of the spine is named the axis or epistropheus. ...
The most distinctive characteristic of the seventh cervical vertebra is the existence of a long and prominent spinous process, hence the name vertebra prominens. ...
The anterior arch forms about one-fifth of the ring: its anterior surface is convex, and presents at its center the anterior tubercle for the attachment of the Longus colli muscles. ...
The posterior arch of a cervical vertebra 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. ...
The transverse processes of the cervical vertebrae are each pierced by the foramen transversarium, which, in the upper six vertebræ, gives passage to the vertebral artery and vein and a plexus of sympathetic nerves. ...
thoracic vertebrae: costal facets (superior, inferior, transverse) A typical thoracic vertebra The thoracic vertebrae (vertebrae thoracales) compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. ...
The superior costal facet (or superior costal fovea) is a site where a rib forms a joint with the top of a vertebra. ...
The inferior costal facet (or inferior costal fovea) is a site where a rib forms a joint with the bottom of a vertebra. ...
The transverse costal facet (or transverse costal fovea) is a site where a rib forms a joint with the transverse process of a vertebra. ...
lumbar vertebrae: accessory process, mammillary process The lumbar vertebrae are the largest segments of the movable part of the vertebral column, and can be distinguished by the absence of a foramen (hole) in the transverse process, and by the absence of facets on the sides of the body. ...
Of the tubercles noticed in connection with the transverse processes of the lower thoracic vertebrae, the inferior is situated at the back part of the base of the transverse process, and is called the accessory process. ...
Of the three tubercles noticed in connection with the transverse processes of the lower thoracic vertebrae, the superior one is connected in the lumbar region with the back part of the superior articular process, and is named the 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 For the record label, see Sacrum Torch The sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. ...
The coccyx is formed of up to five vertebrae. ...
The pelvic surface of sacrum is concave from above downward, and slightly so from side to side. ...
At the ends of the transverse ridges of the pelvic surface of the sacrum are seen the anterior sacral foramina (or pelvic sacral foramina), four in number on either side, somewhat rounded in form, diminishing in size from above downward, and directed lateralward and forward; they give exit to the...
The dorsal surface of sacrum is convex and narrower than the pelvic. ...
Lateral to the articular processes of the sacrum are the four posterior sacral foramina (or dorsal sacral foramina); they are smaller in size and less regular in form than the anterior, and transmit the posterior divisions of the sacral nerves. ...
In the middle line of the dorsal surface of the sacrum, it displays a crest, the median sacral crest, surmounted by three or four tubercles, the rudimentary spinous processes of the upper three or four sacral vertebrae. ...
On the lateral aspect of the sacral groove is a linear series of tubercles produced by the fusion of the articular processes which together form the indistinct medial sacral crest (intermediate sacral crest, sacral articular crest). ...
On the lateral side of the posterior sacral foramina is a series of tubercles, which represent the transverse processes of the sacral vertebrae, and form the lateral sacral crest. ...
The lateral surface of sacrum is broad above, but narrowed into a thin edge below. ...
The base of the sacrum, which is broad and expanded, is directed upward and forward. ...
The laminae of the fifth sacral vertebra, and sometimes those of the fourth, fail to meet behind, and thus a sacral hiatus or deficiency occurs in the posterior wall of the sacral canal. ...
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