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Encyclopedia > Spinous process
A diagram of a thoracic vertebra. Notice the articulations for the ribs
A diagram of a thoracic vertebra. Notice the articulations for the ribs
Different regions of the vertebral column
Different regions of the vertebral column

Vertebrae (singular: vertebra) are the individual bones that make up the vertebral column (aka spine) — a flexuous and flexible column. There are thirty-three (33) vertebrae in humans, including the five that are fused to form the sacrum (the others are separated by intervertebral discs) and the four coccygeal bones which form the tailbone. The upper three regions comprise the remaining 24, and are grouped under the names cervical (7 vertebrae), thoracic (12 vertebrae) and lumbar (5 vertebrae), according to the regions they occupy. This number is sometimes increased by an additional vertebra in one region, or it may be diminished in one region, the deficiency often being supplied by an additional vertebra in another. The number of cervical vertebrae is, however, very rarely increased or diminished. File links The following pages link to this file: Vertebra Wikipedia:Grays Anatomy images with missing articles 2 Thoracic vertebrae Categories: Public domain images ... File links The following pages link to this file: Vertebra Wikipedia:Grays Anatomy images with missing articles 2 Thoracic vertebrae Categories: Public domain images ... Grays illustration of a human femur, a typically recognized bone. ... The human rib cage. ... Image File history File links Download high resolution version (400x622, 96 KB) Labelled by Vsion, using another Public Domain image [1], from Grays Anatomy File links The following pages link to this file: Vertebra Vertebral column User:Vsion/Gallery ... Image File history File links Download high resolution version (400x622, 96 KB) Labelled by Vsion, using another Public Domain image [1], from Grays Anatomy File links The following pages link to this file: Vertebra Vertebral column User:Vsion/Gallery ... The vertebral column seen from the side Different regions (curvatures) of the vertebral column The vertebral column (backbone or spine) is a column of vertebrae situated in the dorsal aspect of the abdomen. ... A miserable stubborn cantankerous old mans, whos actually quite good humoured & an enjoyable compadre to play online alongside if you catch him on a good day. ... The vertebral column seen from the side Different regions (curvatures) of the vertebral column The vertebral column (backbone or spine) is a column of vertebrae situated in the dorsal aspect of the abdomen. ... Image of pelvis. ... Intervertebral discs lie in between adjacent vertebrae in the spine. ... The coccyx is formed of four fused vertebrae. ...


With the exception of the first and second cervical, the true or movable vertebrae (the upper three regions) present certain common characteristics which are best studied by examining one from the middle of the thoracic region.

Contents


General structure

A typical vertebra consists of two essential parts: an anterior (front) segment, which is the vertebral body; and a posterior part – the vertebral or neural arch – which encloses the vertebral foramen. The vertebral arch is formed by a pair of pedicles and a pair of laminae, and supports seven processes, four articular, two transverse, and one spinous. In anatomy, a process (Latin: processus) is a projection or outgrowth of tissue from a larger body. ...


When the vertebrae are articulated with each other, the bodies form a strong pillar for the support of the head and trunk, and the vertebral foramina constitute a canal for the protection of the medulla spinalis (spinal cord or spinal column), while between every pair of vertebrae are two apertures, the intervertebral foramina, one on either side, for the transmission of the spinal nerves and vessels. For other uses of the word head, see head (disambiguation). ... Trunk may be: Look up trunk in Wiktionary, the free dictionary. ... Cross-section through cervical spinal cord. ...


Two transverse processess and one spinous process are posterior to (behind) the vertebral body. The spinous process comes out the back, one transverse process comes out the left, and one on the right. The spinous processes of the cervical and lumbar regions can be felt through the skin. Superior and inferior articular facets on each vertebra act to restrict the range of movement possible. Grays illustration of a human femur, a typically recognized bone. ...


Cervical vertebrae

Note: For more detailed information, see Cervical vertebrae A cervical vertebra Cervical vertebrae (Vertebrae cervicales) are the smallest of the true vertebrae, and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process. ...


These are generally small and delicate. Their spinous processes are short (with the exception of C7 which has the first palpable spinous process), and often split. Numbered top-to-bottom from C1-C7, atlas (C1) and axis (C2), are the vertebrae that allow the neck so much rotation. Specifically, the atlas allows the skull to move up and down, while the axis allows the upper neck to twist left and right. The axis also houses the first intervertebral disk of the spinal column, which ends in the sacrum. First cervical vertebra, or Atlas In anatomy, the Atlas (C1) is the topmost (first) cervical vertebra of the spine. ... In anatomy, the second cervical vertebra (C2) of the spine is named the axis or epistropheus. ... The neck is the part of the body on many limbed vertebrates that distinguishes the head from the torso or trunk. ... A hippopotamus skull A skull, or cranium, is a bony structure of Craniates which serves as the general framework for a head. ...


Thoracic vertebrae

Note: For more detailed information, see Thoracic vertebrae 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. ...


Their spinous processes point downwards, and are long relative to those in other regions. They have surfaces that articulate with the ribs. Some rotation can occur between the thoracic vertebrae, but their connection with the rib cage prevents much flexion or other excursion. Grays illustration of a human femur, a typically recognized bone. ... The human rib cage. ...


Lumbar vertebrae

Note: For more detailed information, see Lumbar vertebrae Categories: Anatomy stubs | Anatomy ...


These vertebrae are very robust in construction, as they must support more weight than other vertebrae. They allow significant flexion and extension, moderate lateral flexion (sidebending), and a small degree of rotation. The discs between these vertebrae create a lumbar lordosis (curvature that is concave posteriorly) in the human spine. In anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum (pelvis). ...


Vertebral development

During the fourth week of embryonic development, the sclerotomes shift their position to surround the spinal cord and the notochord. The sclerotome is made of mesoderm and originates from the ventromedial part of the somites. This column of tissue has a segmented appearance, with alternating areas of dense and less dense areas. Embryogenesis is the process by which the embryo is formed and develops. ... Cross-section through cervical spinal cord. ... It has been suggested that Notogenesis be merged into this article or section. ... It has been suggested that organogenesis be merged into this article or section. ... In the developing vertebrate embryo, somites are masses of mesoderm distributed along the two sides of the neural tube and that will eventually become dermis (dermatome), skeletal muscle (myotome), and vertebrae (sclerotome). ...


As the sclerotome develops, it condenses further eventually developing into the vertebral body. Development of the appropriate shapes of the vertebral bodies is regulated by HOX genes. A diagram of a thoracic vertebra. ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ...


The less dense tissue that separates the sclerotome segments develop into the intervertebral discs. Intervertebral discs lie in between adjacent vertebrae in the spine. ...


The notochord disappears in the sclerotome (vertebral body) segments, but will persist in the region of the intervertebral discs as the nucleus pulposus. The nucleus pulposus and the fibers of the annulus fibrosus make up the intervertebral disc. Nucleus pulposus is the jelly-like substance in the middle of the spinal disc. ...


The primary curves (thoracic and sacral curvatures) form during fetal development. The secondary curves develop after birth. The cervical curvature forms as a result of lifting the head and the lumbar curvature forms as a result of walking.


There are various defects associated with vertebral development. Scoliosis can result from improper fusion of the vertebrae. In Klippel-Feil anomaly patients have fewer than normal cervical vertebrae, along with other associated birth defects. One of the most serious defects is failure of the vertebral arches to fuse. This results in a condition called spina bifida. There are several variations of spina bifida that reflect the severity of the defect. Klippel-Feil syndrome is a rare disorder characterized by the congenital fusion of any 2 of the 7 cervical (neck) vertebrae. ...


See also

Grays illustration of a human femur, a typically recognized bone. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... Clearing the cervical spine after blunt multitrauma is an important part of emergency medical care, aiming to avoid preventable quadriplegia due to undiagnosed unstable cervical spine injuries. ...

References

  • Gray's Anatomy: The Vertebral column - The 1917 Gray's Anatomy is available via the Bartleby project. It is available with full colour diagrams, and provides an excellent starting point in anatomy, as well as a relatively complete source for gross anatomy. This article was copied and pasted from the 1917 Gray's Anatomy, which is in the public domain.
  • Smart implant will help broken vertebra - An article from IsraCast

  Results from FactBites:
 
XII. Surface Anatomy and Surface Markings. 4. Surface Markings of the Back. Gray, Henry. 1918. Anatomy of the Human ... (371 words)
The root of the spine of the scapula is on a level with the tip of the spinous process of the third thoracic vertebra, and the inferior angle with that of the seventh.
The highest point of the iliac crest is on a level with the spinous process of the fourth lumbar, and the posterior superior iliac spine with that of the second sacral.
The transverse process of the sixth cervical vertebra is opposite the cricoid cartilage; below it is the transverse process of the seventh and occasionally a cervical rib.
Early American Manual Therapy (5002 words)
This spinous process is on a level with the superior portion of the spine of the scapulae and it may be detected and located by placing the thumbs in a line with the fingers when they are placed above the spines of the scapulae on both sides.
The location of the spinous process of the third thoracic vertebra corresponds to the level of the inner edge of the spines of the scapulae and it is the second process palpated below the first thoracic spinous process.
The spinous process of the tenth thoracic vertebra is about a finger's breadth below the attachments of the last two ribs, and it may be determined by the prominence of the tenth pair of ribs in the axillary line by following them to the spine.
  More results at FactBites »


 

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