lab+2

**VERTEBRAL COLUMN** The vertebral column, along with the sternum and ribs, makes up the trunk of the skeleton. The 26 bones of the vertebral column are arranged into five regions: **cervical, thoracic, lumbar, sacral, and coccygeal**. Between adjacent vertebrae, from the first cervical (atlas) to the sacrum, are **intervertebral discs** that form strong joints, permit various movements of the vertebral column, and absorb vertical shock.


 * //Regions of the Vertebral Column//

Cervical Region** There are **7 cervical vertebrae**. The first cervical vertebra is the //**atlas**// and **supports the skull**. The second cervical vertebra is the //**axis**//, which **permits side-to-side rotation of the head** There are **12 thoracic vertebrae** .These vertebrae articulate with the ribs. There are **5 lumbar vertebrae**. They are the largest and strongest vertebrae in the column. The //sacrum// is formed by the **union of 5 sacral vertebrae** and serves as a strong foundation for the pelvic girdle. The //coccyx// is formed by the fusion of 4 coccygeal vertebrae.
 * Thoracic Region**
 * Lumbar Region**
 * Sacrum**
 * Coccyx**


 * TYPICAL THORACIC VERTEBRAE**


 * 1. || Spinous Process ||
 * 2. || Lamina ||
 * 3. || Superior Articular Surface ||
 * 4. || Transverse Process ||
 * 5. || Pedicle ||
 * 6. || Body ||
 * 7. || Vertebral Foramen ||
 * 8. || Articular Facet for Rib ||
 * 9. || Inferior Articular Surface ||


 * [[image:skull_ibank.gif align="right" link="BIO107LAB"]][|VERTEBRAE AND SPINAL COLUMN]

[|VERTEBRAE AND SPINAL COLUMN]

[|ATLAS]

[|AXIS]

[|CERVICAL VERTEBRAE]

[|THORACIC VERTEBRAE]

[|LUMBAR VERTEBRAE]

[|SACRUM & COCCYX]

** =The Vertebral Column and Vertebrae= The Vertebral Column (Spinal Column) supports the head and encloses the spinal cord. The spinal column is comprised of 26 individual bones, these bones are refered to as vertebrae. The spinal column is divided into 5 different areas containing groups of vertebrae and are grouped as follows:
 * [[image:http://www.apparelyzed.com/_images/content/shim.gif width="100" height="424"]] || [[image:http://www.apparelyzed.com/_images/content/spine/animatedspine.gif width="112" height="424" caption="spinal column"]] ||

7 cervical vertebrae in the neck. 12 thoracic vertebrae in the upper back corresponding to each pair of ribs. 5 lumbar vertebrae in the lower back. 5 sacral vertebrae which are fused together to form 1 bone called the sacrum. 4 coccygeal vertebrae that are fused together to form the coccyx or tailbone.

The vertebrae are refered to by their name and number, counting down from the top of the spinal column as follows:

The cervical vertebrae are C1 - C7 The thoracic vertebrae are T1 –T12 The lumbar are L1 – L5 The sacrum and coccyx do not have numbers and each is thought of as one bone. Spinal nerves exit the sacrum and coccyx at levels (Foramen) within the main structure of each vertebra.

**General Characteristics of a Vertebra**
A **typical vertebra** consists of two essential parts—viz., an anterior segment, the **body**, and a posterior part, the vertebral or **neural arch**; these enclose a **foramen**, the **vertebral foramen**. The **vertebral arch** consists of a pair of **pedicles** and a pair of laminae, and supports seven processes—viz., four articular, two transverse, and one spinous. 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), 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.
 * [[image:http://www.apparelyzed.com/_images/content/spine/vertebrae-spine.jpg width="270" height="239"]]
 * FIG. 1 - A typical thoracic vertebra, viewed from above.**
 * FIG. 2– Sagittal section of a lumbar vertebra.** ||
 * Body (corpus vertebrae)**.—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. In front, the body is convex from side to side and concave from above downward. Behind, it is flat from above downward and slightly concave from side to side. Its anterior surface presents a few small apertures, for the passage of nutrient vessels; on the posterior surface is a single large, irregular aperture, or occasionally more than one, for the exit of the basi-vertebral veins from the body of the vertebra.
 * Pedicles (radices arci vertebrae)**.„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 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, already referred to.
 * Laminae**.„The laminae are two broad plates directed backward and medialward from the pedicles. They fuse in the middle line posteriorly, and so complete the posterior boundary of the vertebral foramen. Their upper borders and the lower parts of their anterior surfaces are rough for the attachment of the ligamenta flava.
 * Processes.„Spinous Process (processus spinosus)**.„The spinous process is directed backward and downward from the junction of the laminae, and serves for the attachment of muscles and ligaments.
 * Articular Processes**.„The articular processes, two superior and two inferior, spring from the junctions of the pedicles and laminae. 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. The articular surfaces are coated with hyaline cartilage.
 * Transverse Processes (processus transversi)**.„The transverse processes, 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.
 * Structure of a Vertebra (Fig. 2)**.„The body is composed of cancellous tissue, covered by a thin coating of compact bone; the latter is perforated by numerous orifices, some of large size for the passage of vessels; the interior of the bone is traversed by one or two large canals, for the reception of veins, which converge toward a single large, irregular aperture, or several small apertures, at the posterior part of the body. The thin bony lamellae of the cancellous tissue are more pronounced in lines perpendicular to the upper and lower surfaces and are developed in response to greater pressure in this direction (Fig. 2). The arch and processes projecting from it have thick coverings of compact tissue.


 * 1. || Jugular Notch ||
 * 2. || Manubrium ||
 * 3. || Sternal Angle ||
 * 4. || Body (Gladiolus) ||
 * 5. || Xiphoid Process ||

__The term //thorax// refers to the entire chest. The skeletal part of the thorax (a bony cage) consists of the //sternum//, //costal cartilages//, //ribs//, and the //bodies of the thoracic vertebrae//__ __The thoracic cage encloses and protects the organs in the thoracic and superior abdominal cavities. It also provides support for the bones of the shoulder girdle and upper limbs.__
 * THORAX**

__The //sternum// is located on the anterior midline of the thoracic wall. It con sists of three parts: //manubrium//, //body//, and //xiphoid process//__
 * __Sternum__**

__The 12 pairs of ribs give structural support to the sides of the thoracic cavity. The first 7 pairs of ribs are called //true ribs//; the remaining five pairs, //false ribs// (with the last two false ribs called //floating ribs//).__
 * __Ribs__**


 * 1. || Articular Facet of Rib ||
 * 2. || Interarticular Crest ||
 * 3. || Neck ||
 * 4. || Articular Portion of Tubercle ||
 * 5. || Nonarticular Portion of Tubercle ||
 * 6. || Angle of Rib ||
 * 7. || Costal Groove ||
 * 8. || Body of Rib ||
 * 9. || Articular Facet of Transverse Process ||
 * 10. || Transverse Process ||
 * 11. || Spinous Process ||
 * 12. || Lamina ||
 * 13. || Vertebral Foramen ||



[|RIBS]

[|STERNUM]