An important artery that supplies the brain ascends up the neck by passing through these openings. The superior and inferior articular processes of the cervical vertebrae are flattened and largely face upward or downward, respectively. The first and second cervical vertebrae are further modified, giving each a distinctive appearance. The first cervical C1 vertebra is also called the atlas , because this is the vertebra that supports the skull on top of the vertebral column in Greek mythology, Atlas was the god who supported the heavens on his shoulders.
The C1 vertebra does not have a body or spinous process. Instead, it is ring-shaped, consisting of an anterior arch and a posterior arch. The transverse processes of the atlas are longer and extend more laterally than do the transverse processes of any other cervical vertebrae. The superior articular processes face upward and are deeply curved for articulation with the occipital condyles on the base of the skull. The inferior articular processes are flat and face downward to join with the superior articular processes of the C2 vertebra.
The second cervical C2 vertebra is called the axis , because it serves as the axis for rotation when turning the head toward the right or left. The axis resembles typical cervical vertebrae in most respects, but is easily distinguished by the dens odontoid process , a bony projection that extends upward from the vertebral body. The dens joins with the inner aspect of the anterior arch of the atlas, where it is held in place by transverse ligament.
The bodies of the thoracic vertebrae are larger than those of cervical vertebrae Figure 6. The characteristic feature for a typical midthoracic vertebra is the spinous process, which is long and has a pronounced downward angle that causes it to overlap the next inferior vertebra.
The superior articular processes of thoracic vertebrae face anteriorly and the inferior processes face posteriorly. These orientations are important determinants for the type and range of movements available to the thoracic region of the vertebral column.
Thoracic vertebrae have several additional articulation sites, each of which is called a facet , where a rib is attached. These are for articulation with the head end of a rib. An additional facet is located on the transverse process for articulation with the tubercle of a rib. Lumbar vertebrae carry the greatest amount of body weight and are thus characterized by the large size and thickness of the vertebral body Figure 6.
They have short transverse processes and a short, blunt spinous process that projects posteriorly. The articular processes are large, with the superior process facing backward and the inferior facing forward. The sacrum is a triangular-shaped bone that is thick and wide across its superior base where it is weight bearing and then tapers down to an inferior, non-weight bearing apex Figure 6. It is formed by the fusion of five sacral vertebrae, a process that does not begin until after the age of The coccyx, or tailbone, is derived from the fusion of four very small coccygeal vertebrae see Figure 6.
It articulates with the inferior tip of the sacrum. It is not weight bearing in the standing position, but may receive some body weight when sitting. Watch this second animation to see one possible treatment for a herniated disc, removing and replacing the damaged disc with an artificial one that allows for movement between the adjacent certebrae.
How could lifting a heavy object produce pain in a lower limb? Use this tool to identify the bones, intervertebral discs, and ligaments of the vertebral column. The thickest portions of the anterior longitudinal ligament and the supraspinous ligament are found in which regions of the vertebral column? Chiropractors are health professionals who use nonsurgical techniques to help patients with musculoskeletal system problems that involve the bones, muscles, ligaments, tendons, or nervous system.
They treat problems such as neck pain, back pain, joint pain, or headaches. If needed, they will refer the patient to other medical specialists. Chiropractors use a drug-free, hands-on approach for patient diagnosis and treatment. They can recommend therapeutic or rehabilitative exercises, and some also include acupuncture, massage therapy, or ultrasound as part of the treatment program.
In addition to those in general practice, some chiropractors specialize in sport injuries, neurology, orthopaedics, pediatrics, nutrition, internal disorders, or diagnostic imaging. To become a chiropractor, students must have 3—4 years of undergraduate education, attend an accredited, four-year Doctor of Chiropractic D.
It also provides a base for numerous muscle attachments and articulations with other bones. The strength and flexibility of this structure is generated by the structure of the individual vertebrae. Comprised of bone and cartilage, the configuration of a vertebra varies based on its location within the body, although there are common features associated with those of the upper region. The vertebral arch is formed from two, short, thick processes called pediments that extend posteriorly from the lateral sides of the vertebral body, before joining together at the midline with the laminae.
Oblique view of cervical vertebra : The parts of a human vertebra. Four articular processes originate from the joint between the pedicles and laminae, two point superiorly and two point inferiorly.
They interact with the zyhapophysis, a socket for the articular processes, of the adjacent vertebrae to make the spine more stable and to facilitate a small degree of articulation.
A single spinous process projects backwards and downwards from the center of the vertebral arch and it serves as a major attachment point for muscles and ligaments of the back. The two transverse processes project laterally from the join between the pedicle and lamina and also serve as an attachment point for muscles and ligaments of the back. The transverse processes articulate with the ribs in conjunction with the vertebral body.
The vertebrae of the spinal column are divided into five regions: cervical, thoracic, lumbar, sacral, and coccyx. The vertebrae comprising the spinal column can be divided into five regions, based on the five varying curvatures of the spine. The upper three regions of the spinal column are termed the cervical, thoracic, and lumbar; they contain individually jointed vertebrae.
The two lower regions—the sacrum and coccyx, or tailbone—are formed from fused vertebrae. Vertebrae are given an alphanumeric descriptor, with the initial letter derived from the region they are located in followed by a digit that increases moving down the region.
For example, the most superior cervical vertebrae is termed C1 and the most inferior C7, which is then followed by the T1 vertebrae of the thoracic region. The cervical region of the spine is the most superior and contains seven small vertebrae. The main function of the cervical region is to facilitate attachment of the skull to the spine, protect the spinal cord over the exposed neck and shoulder region, and support the body. Cervical vertebra, lateral view : The lateral view of a typical cervical vertebra.
The twelve thoracic vertebrae are located inferiorly to the cervical region. They are larger than the cervical vertebrae and increase in size moving inferiorly to the lumbar region.
Thoracic vertebra : Image of a typical thoracic vertebra. The five lumbar vertebrae are the largest vertebral bones and increase in size when moving inferiorly. The second cervical C2 vertebra is called the axis , because it serves as the axis for rotation when turning the head toward the right or left. The axis resembles typical cervical vertebrae in most respects, but is easily distinguished by the dens odontoid process , a bony projection that extends upward from the vertebral body.
The dens joins with the inner aspect of the anterior arch of the atlas, where it is held in place by transverse ligament. Thoracic Vertebrae The bodies of the thoracic vertebrae are larger than those of cervical vertebrae Figure.
The characteristic feature for a typical midthoracic vertebra is the spinous process, which is long and has a pronounced downward angle that causes it to overlap the next inferior vertebra. The superior articular processes of thoracic vertebrae face anteriorly and the inferior processes face posteriorly.
These orientations are important determinants for the type and range of movements available to the thoracic region of the vertebral column. Thoracic vertebrae have several additional articulation sites, each of which is called a facet , where a rib is attached. These are for articulation with the head end of a rib. An additional facet is located on the transverse process for articulation with the tubercle of a rib. Rib Articulation in Thoracic Vertebrae Thoracic vertebrae have superior and inferior articular facets on the vertebral body for articulation with the head of a rib, and a transverse process facet for articulation with the rib tubercle.
Lumbar Vertebrae Lumbar vertebrae carry the greatest amount of body weight and are thus characterized by the large size and thickness of the vertebral body Figure. They have short transverse processes and a short, blunt spinous process that projects posteriorly.
The articular processes are large, with the superior process facing backward and the inferior facing forward. Sacrum and Coccyx The sacrum is a triangular-shaped bone that is thick and wide across its superior base where it is weight bearing and then tapers down to an inferior, non-weight bearing apex Figure.
It is formed by the fusion of five sacral vertebrae, a process that does not begin until after the age of On the anterior surface of the older adult sacrum, the lines of vertebral fusion can be seen as four transverse ridges. Similarly, the fused transverse processes of the sacral vertebrae form the lateral sacral crest. The sacral promontory is the anterior lip of the superior base of the sacrum.
Lateral to this is the roughened auricular surface, which joins with the ilium portion of the hipbone to form the immobile sacroiliac joints of the pelvis. Passing inferiorly through the sacrum is a bony tunnel called the sacral canal , which terminates at the sacral hiatus near the inferior tip of the sacrum. Each of these openings is called a posterior dorsal sacral foramen or anterior ventral sacral foramen. These openings allow for the anterior and posterior branches of the sacral spinal nerves to exit the sacrum.
The superior articular process of the sacrum , one of which is found on either side of the superior opening of the sacral canal, articulates with the inferior articular processes from the L5 vertebra. The coccyx, or tailbone, is derived from the fusion of four very small coccygeal vertebrae see Figure. It articulates with the inferior tip of the sacrum. It is not weight bearing in the standing position, but may receive some body weight when sitting. Intervertebral Discs and Ligaments of the Vertebral Column The bodies of adjacent vertebrae are strongly anchored to each other by an intervertebral disc.
This structure provides padding between the bones during weight bearing, and because it can change shape, also allows for movement between the vertebrae. Although the total amount of movement available between any two adjacent vertebrae is small, when these movements are summed together along the entire length of the vertebral column, large body movements can be produced. Ligaments that extend along the length of the vertebral column also contribute to its overall support and stability.
An intervertebral disc is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies see Figure. Each disc is anchored to the bodies of its adjacent vertebrae, thus strongly uniting these. The discs also provide padding between vertebrae during weight bearing. Because of this, intervertebral discs are thin in the cervical region and thickest in the lumbar region, which carries the most body weight.
In total, the intervertebral discs account for approximately 25 percent of your body height between the top of the pelvis and the base of the skull.
Intervertebral discs are also flexible and can change shape to allow for movements of the vertebral column. Each intervertebral disc consists of two parts. The anulus fibrosus is the tough, fibrous outer layer of the disc. Inside is the nucleus pulposus , consisting of a softer, more gel-like material.
It has a high water content that serves to resist compression and thus is important for weight bearing. With increasing age, the water content of the nucleus pulposus gradually declines. This causes the disc to become thinner, decreasing total body height somewhat, and reduces the flexibility and range of motion of the disc, making bending more difficult. The gel-like nature of the nucleus pulposus also allows the intervertebral disc to change shape as one vertebra rocks side to side or forward and back in relation to its neighbors during movements of the vertebral column.
Thus, bending forward causes compression of the anterior portion of the disc but expansion of the posterior disc. Watch this second animation to see one possible treatment for a herniated disc, removing and replacing the damaged disc with an artificial one that allows for movement between the adjacent certebrae.
How could lifting a heavy object produce pain in a lower limb? Adjacent vertebrae are united by ligaments that run the length of the vertebral column along both its posterior and anterior aspects Figure. These serve to resist excess forward or backward bending movements of the vertebral column, respectively.
The anterior longitudinal ligament runs down the anterior side of the entire vertebral column, uniting the vertebral bodies. It serves to resist excess backward bending of the vertebral column.
Protection against this movement is particularly important in the neck, where extreme posterior bending of the head and neck can stretch or tear this ligament, resulting in a painful whiplash injury. Prior to the mandatory installation of seat headrests, whiplash injuries were common for passengers involved in a rear-end automobile collision. The supraspinous ligament is located on the posterior side of the vertebral column, where it interconnects the spinous processes of the thoracic and lumbar vertebrae.
This strong ligament supports the vertebral column during forward bending motions. The nuchal ligament is attached to the cervical spinous processes and extends upward and posteriorly to attach to the midline base of the skull, out to the external occipital protuberance.
It supports the skull and prevents it from falling forward. This ligament is much larger and stronger in four-legged animals such as cows, where the large skull hangs off the front end of the vertebral column. You can easily feel this ligament by first extending your head backward and pressing down on the posterior midline of your neck. Then tilt your head forward and you will fill the nuchal ligament popping out as it tightens to limit anterior bending of the head and neck. Additional ligaments are located inside the vertebral canal, next to the spinal cord, along the length of the vertebral column.
The posterior longitudinal ligament is found anterior to the spinal cord, where it is attached to the posterior sides of the vertebral bodies. This consists of a series of short, paired ligaments, each of which interconnects the lamina regions of adjacent vertebrae.
The ligamentum flavum has large numbers of elastic fibers, which have a yellowish color, allowing it to stretch and then pull back. Both of these ligaments provide important support for the vertebral column when bending forward.
Use this tool to identify the bones, intervertebral discs, and ligaments of the vertebral column. The thickest portions of the anterior longitudinal ligament and the supraspinous ligament are found in which regions of the vertebral column?
Chiropractor Chiropractors are health professionals who use nonsurgical techniques to help patients with musculoskeletal system problems that involve the bones, muscles, ligaments, tendons, or nervous system. They treat problems such as neck pain, back pain, joint pain, or headaches. If needed, they will refer the patient to other medical specialists. Chiropractors use a drug-free, hands-on approach for patient diagnosis and treatment. They can recommend therapeutic or rehabilitative exercises, and some also include acupuncture, massage therapy, or ultrasound as part of the treatment program.
In addition to those in general practice, some chiropractors specialize in sport injuries, neurology, orthopaedics, pediatrics, nutrition, internal disorders, or diagnostic imaging. To become a chiropractor, students must have 3—4 years of undergraduate education, attend an accredited, four-year Doctor of Chiropractic D.
With the aging of the baby-boom generation, employment for chiropractors is expected to increase. The vertebral column forms the neck and back. The vertebral column originally develops as 33 vertebrae, but is eventually reduced to 24 vertebrae, plus the sacrum and coccyx.
The vertebrae are divided into the cervical region C1—C7 vertebrae , the thoracic region T1—T12 vertebrae , and the lumbar region L1—L5 vertebrae. The sacrum arises from the fusion of five sacral vertebrae and the coccyx from the fusion of four small coccygeal vertebrae. The vertebral column has four curvatures, the cervical, thoracic, lumbar, and sacrococcygeal curves. The thoracic and sacrococcygeal curves are primary curves retained from the original fetal curvature.
The cervical and lumbar curves develop after birth and thus are secondary curves. The cervical curve develops as the infant begins to hold up the head, and the lumbar curve appears with standing and walking. A typical vertebra consists of an enlarged anterior portion called the body, which provides weight-bearing support. Attached posteriorly to the body is a vertebral arch, which surrounds and defines the vertebral foramen for passage of the spinal cord.
The vertebral arch consists of the pedicles, which attach to the vertebral body, and the laminae, which come together to form the roof of the arch. Arising from the vertebral arch are the laterally projecting transverse processes and the posteriorly oriented spinous process. The superior articular processes project upward, where they articulate with the downward projecting inferior articular processes of the next higher vertebrae.
A typical cervical vertebra has a small body, a bifid Y-shaped spinous process, and U-shaped transverse processes with a transverse foramen. In addition to these characteristics, the axis C2 vertebra also has the dens projecting upward from the vertebral body. The atlas C1 vertebra differs from the other cervical vertebrae in that it does not have a body, but instead consists of bony ring formed by the anterior and posterior arches.
The atlas articulates with the dens from the axis. A typical thoracic vertebra is distinguished by its long, downward projecting spinous process. Thoracic vertebrae also have articulation facets on the body and transverse processes for attachment of the ribs.
Lumbar vertebrae support the greatest amount of body weight and thus have a large, thick body. They also have a short, blunt spinous process. The sacrum is triangular in shape.
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