What Is The Size And Shape Of The Cervical Vertebrae
Learning Objectives
- Describe each region of the vertebral column and the number of basic in each region
- Discuss the curves of the vertebral cavalcade and how these change subsequently nascency
- Draw a typical vertebra and determine the distinguishing characteristics for vertebrae in each vertebral region and features of the sacrum and the coccyx
- Regions of the Vertebral Column
- Curvatures of the Vertebral Cavalcade
- General Structure of a Vertebra
- Regional Modifications of Vertebrae
- Cervical Vertebrae
- Thoracic Vertebrae
- Lumbar Vertebrae
- Sacrum and Coccyx
Regions of the Vertebral Cavalcade
The vertebral column originally develops equally a serial of 33 vertebrae, simply this number is eventually reduced to 24 vertebrae, plus the sacrum and coccyx. The vertebral column is subdivided into five regions, with the vertebrae in each expanse named for that region and numbered in descending order. In the cervix, there are seven cervical vertebrae, each designated with the letter "C" followed by its number. Superiorly, the C1 vertebra articulates (forms a joint) with the occipital condyles of the skull. Inferiorly, C1 articulates with the C2 vertebra, and so on. Below these are the 12 thoracic vertebrae, designated T1–T12. The lower back contains the L1–L5 lumbar vertebrae. The single sacrum, which is also part of the pelvis, is formed past the fusion of five sacral vertebrae. Similarly, the coccyx, or tailbone, results from the fusion of four small coccygeal vertebrae. However, the sacral and coccygeal fusions practise non start until age twenty and are not completed until center age.
An interesting anatomical fact is that well-nigh all mammals take seven cervical vertebrae, regardless of body size. This ways that there are large variations in the size of cervical vertebrae, ranging from the very small cervical vertebrae of a shrew to the greatly elongated vertebrae in the neck of a giraffe. In a total-grown giraffe, each cervical vertebra is eleven inches alpine.
Curvatures of the Vertebral Column
The adult vertebral cavalcade does not form a straight line, but instead has four curvatures along its length – cervical, thoracic, lumbar, pelvic (sacrum/coccyx) (see Figure six.29). These curves increase the vertebral column's strength, flexibility, and ability to absorb shock. When the load on the spine is increased, by carrying a heavy backpack for instance, the curvatures increase in depth (become more curved) to arrange the extra weight. They so jump back when the weight is removed.
Disorders associated with the curvature of the spine include kyphosis (an excessive posterior curvature of the thoracic region), lordosis (an excessive inductive curvature of the lumbar region), and scoliosis (an aberrant, lateral curvature, accompanied past twisting of the vertebral column).
Developmental anomalies, pathological changes, or obesity tin enhance the normal vertebral cavalcade curves, resulting in the development of abnormal or excessive curvatures (Figure vi.30). Kyphosis, also referred to as humpback or hunchback, is an excessive posterior curvature of the thoracic region. This can develop when osteoporosis causes weakening and erosion of the anterior portions of the upper thoracic vertebrae, resulting in their gradual collapse (Figure half dozen.31). Lordosis, or swayback, is an excessive anterior curvature of the lumbar region and is virtually commonly associated with obesity or belatedly pregnancy. The accumulation of body weight in the abdominal region results an anterior shift in the line of gravity that carries the weight of the body. This causes in an anterior tilt of the pelvis and a pronounced enhancement of the lumbar curve.
Scoliosis is an abnormal, lateral curvature, accompanied by twisting of the vertebral column. Compensatory curves may also develop in other areas of the vertebral column to help maintain the head positioned over the feet. Scoliosis is the nigh common vertebral abnormality among girls. The cause is usually unknown, only information technology may result from weakness of the back muscles, defects such equally differential growth rates in the correct and left sides of the vertebral column, or differences in the length of the lower limbs. When nowadays, scoliosis tends to become worse during adolescent growth spurts. Although almost individuals do non require treatment, a back caryatid may be recommended for growing children. In extreme cases, surgery may be required.
Interactive Link
Osteoporosis is a common age-related bone disease in which bone density and forcefulness is decreased. Watch this video to get a improve understanding of how thoracic vertebrae may become weakened and may fracture due to this affliction. How may vertebral osteoporosis contribute to kyphosis?
General Structure of a Vertebra
Inside the dissimilar regions of the vertebral cavalcade, vertebrae vary in size and shape, but they all follow a similar structural pattern. A typical vertebra will consist of a body, a vertebral curvation, and vii processes (Figure 6.32).
The torso is the anterior portion of each vertebra and is the part that supports the torso weight. Because of this, the vertebral bodies progressively increment in size and thickness going down the vertebral column. The bodies of next vertebrae are separated and strongly united past an intervertebral disc.
The vertebral arch forms the posterior portion of each vertebra. Information technology consists of four parts, the correct and left pedicles and the right and left laminae. Each pedicle forms ane of the lateral sides of the vertebral curvation. The pedicles are anchored to the posterior side of the vertebral body. Each lamina forms role of the posterior roof of the vertebral curvation. The large opening between the vertebral arch and torso is the vertebral foramen , which contains the spinal cord. In the intact vertebral column, the vertebral foramina of all of the vertebrae marshal to form the vertebral (spinal) canal , which serves as the bony protection and passageway for the spinal string downwards the back. When the vertebrae are aligned together in the vertebral column, notches in the margins of the pedicles of side by side vertebrae together form an intervertebral foramen , the opening through which a spinal nerve exits from the vertebral column (Figure 6.32).
Seven processes arise from the vertebral arch. Each paired transverse process projects laterally and arises from the junction point between the pedicle and lamina. The single spinous procedure (vertebral spine) projects posteriorly at the midline of the dorsum. The vertebral spines tin can easily be felt equally a series of bumps just under the skin downward the eye of the back. The transverse and spinous processes serve as important musculus attachment sites. A superior articular process extends or faces upward, and an inferior articular procedure faces or projects downward on each side of a vertebrae. The paired superior articular processes of one vertebra join with the corresponding paired junior articular processes from the next higher vertebra. These junctions form slightly moveable joints between the next vertebrae. The shape and orientation of the articular processes vary in different regions of the vertebral column and play a major role in determining the type and range of motion bachelor in each region.
Regional Modifications of Vertebrae
In addition to the general characteristics of a typical vertebra described above, vertebrae also display characteristic size and structural features that vary betwixt the dissimilar vertebral column regions. Thus, cervical vertebrae are smaller than lumbar vertebrae due to differences in the proportion of trunk weight that each supports. Thoracic vertebrae have sites for rib attachment, and the vertebrae that give rising to the sacrum and coccyx have fused together into single bones.
Cervical Vertebrae
Typical cervical vertebrae , such every bit C4 or C5, have several feature features that differentiate them from thoracic or lumbar vertebrae (Figure six.33). Cervical vertebrae accept a minor trunk, reflecting the fact that they conduct the least amount of body weight. Cervical vertebrae usually accept a bifid (Y-shaped) barbed process. The spinous processes of the C3–C6 vertebrae are brusque, but the spine of C7 is much longer. You can find these vertebrae past running your finger down the midline of the posterior neck until you run across the prominent C7 spine located at the base of the neck. The transverse processes of the cervical vertebrae are sharply curved (U-shaped) to allow for passage of the cervical spinal nerves. Each transverse process likewise has an opening called the transverse foramen . An important artery that supplies the brain ascends up the neck past passing through these openings. The superior and junior articular processes of the cervical vertebrae are flattened and largely face upwardly or downwardly, respectively.
The beginning and 2nd cervical vertebrae are farther modified, giving each a distinctive appearance. The first cervical (C1) vertebra is too 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 trunk or barbed process. Instead, it is band-shaped, consisting of an anterior curvation and a posterior arch . The transverse processes of the atlas are longer and extend more laterally than do the transverse processes of whatever other cervical vertebrae. The superior articular processes confront 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 chosen the axis , because information technology serves as the axis for rotation when turning the caput toward the right or left. The axis resembles typical cervical vertebrae in almost respects, but is easily distinguished by the dens (odontoid procedure), a bony projection that extends upwards from the vertebral torso. The dens joins with the inner aspect of the inductive arch of the atlas, where it is held in identify by transverse ligament.
Thoracic Vertebrae
The bodies of the thoracic vertebrae are larger than those of cervical vertebrae (Figure 6.34). The characteristic characteristic for a typical midthoracic vertebra is the spinous process, which is long and has a pronounced downwards bending that causes it to overlap the adjacent inferior vertebra. The superior articular processes of thoracic vertebrae confront anteriorly and the inferior processes face posteriorly. These orientations are of import determinants for the blazon and range of movements available to the thoracic region of the vertebral cavalcade.
Thoracic vertebrae have several additional articulation sites, each of which is called a facet , where a rib is attached. Most thoracic vertebrae have ii facets located on the lateral sides of the torso, each of which is called a costal facet (costal = "rib"). 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
Lumbar vertebrae behave the greatest amount of body weight and are thus characterized by the large size and thickness of the vertebral body (Figure 6.36). They have short transverse processes and a short, edgeless spinous procedure that projects posteriorly. The articular processes are big, with the superior process facing backward and the inferior facing frontwards.
Sacrum and Coccyx
The sacrum is a triangular-shaped os that is thick and wide beyond its superior base of operations where it is weight bearing and then tapers downward to an inferior, non-weight bearing apex (Effigy 6.37). It is formed past the fusion of v sacral vertebrae, a procedure that does non begin until after the age of xx.
The coccyx, or tailbone, is derived from the fusion of four very small coccygeal vertebrae (see Figure 6.37). It articulates with the inferior tip of the sacrum. It is non weight bearing in the standing position, but may receive some body weight when sitting.
Interactive Links
Watch this blitheness to run into what it means to "sideslip" a disk. Sentinel this 2nd animation to see one possible treatment for a herniated disc, removing and replacing the damaged disc with an bogus one that allows for movement between the adjacent certebrae. How could lifting a heavy object produce pain in a lower limb?
Interactive Link
Use this tool to place the bones, intervertebral discs, and ligaments of the vertebral column. The thickest portions of the anterior longitudinal ligament and the supraspinous ligament are institute in which regions of the vertebral column?
Career Connections: Chiropractor
Chiropractors are wellness professionals who use nonsurgical techniques to help patients with musculoskeletal arrangement problems that involve the bones, muscles, ligaments, tendons, or nervous system. They treat issues such as neck pain, back pain, joint pain, or headaches. Chiropractors focus on the patient's overall health and tin can also provide counseling related to lifestyle issues, such as diet, do, or slumber problems. If needed, they volition refer the patient to other medical specialists.
Chiropractors use a drug-free, hands-on approach for patient diagnosis and treatment. They will perform a physical exam, appraise the patient'southward posture and spine, and may perform boosted diagnostic tests, including taking 10-ray images. They primarily apply transmission techniques, such as spinal manipulation, to adjust the patient'due south spine or other joints. They can recommend therapeutic or rehabilitative exercises, and some also include acupuncture, massage therapy, or ultrasound equally office 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–iv years of undergraduate education, attend an accredited, iv-year Doctor of Chiropractic (D.C.) degree program, and laissez passer a licensure examination to be licensed for practise in their state. With the aging of the infant-nail generation, employment for chiropractors is expected to increase.
What Is The Size And Shape Of The Cervical Vertebrae,
Source: https://courses.lumenlearning.com/nemcc-ap/chapter/the-vertebral-column/
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