The clavicular notch is the shallow depression located on either side at the superior-lateral margins of the manubrium.
This is the site of the sternoclavicular joint, between the sternum and clavicle. The first ribs also attach to the manubrium. The elongated, central portion of the sternum is the body. The manubrium and body join together at the sternal angle , so called because the junction between these two components is not flat, but forms a slight bend.
The second rib attaches to the sternum at the sternal angle. Since the first rib is hidden behind the clavicle, the second rib is the highest rib that can be identified by palpation. Thus, the sternal angle and second rib are important landmarks for the identification and counting of the lower ribs. Ribs 3—7 attach to the sternal body. The inferior tip of the sternum is the xiphoid process.
This small structure is cartilaginous early in life, but gradually becomes ossified starting during middle age. Each rib is a curved, flattened bone that contributes to the wall of the thorax. The ribs articulate posteriorly with the T1—T12 thoracic vertebrae, and most attach anteriorly via their costal cartilages to the sternum.
There are 12 pairs of ribs. The ribs are numbered 1—12 in accordance with the thoracic vertebrae. The posterior end of a typical rib is called the head of the rib see Figure. This region articulates primarily with the costal facet located on the body of the same numbered thoracic vertebra and to a lesser degree, with the costal facet located on the body of the next higher vertebra.
Lateral to the head is the narrowed neck of the rib. A small bump on the posterior rib surface is the tubercle of the rib , which articulates with the facet located on the transverse process of the same numbered vertebra.
The remainder of the rib is the body of the rib shaft. Just lateral to the tubercle is the angle of the rib , the point at which the rib has its greatest degree of curvature. The angles of the ribs form the most posterior extent of the thoracic cage. In the anatomical position, the angles align with the medial border of the scapula.
A shallow costal groove for the passage of blood vessels and a nerve is found along the inferior margin of each rib.
The bony ribs do not extend anteriorly completely around to the sternum. Instead, each rib ends in a costal cartilage. These cartilages are made of hyaline cartilage and can extend for several inches. Most ribs are then attached, either directly or indirectly, to the sternum via their costal cartilage see Figure.
The ribs are classified into three groups based on their relationship to the sternum. Ribs 1—7 are classified as true ribs vertebrosternal ribs. The costal cartilage from each of these ribs attaches directly to the sternum.
Ribs 8—12 are called false ribs vertebrochondral ribs. However, T5-T8 have the greatest rotation ability of the thoracic region. Thoracic vertebrae have superior articular facets that face in a posterolateral direction. The spinous process is long, relative to other regions, and is directed posteroinferiorly. This projection gradually increases as the column descends before decreasing rapidly from T9-T The intervertebral disc height is, on average, the least of the vertebral regions.
They alone articulate with the first rib; C7 has no costal facets. T1 does, however, have typical inferior demifacets for articulation with the second rib. T1 also has a long, almost horizontal spinous process, similar to a cervical vertebra that may be as long as the vertebra prominens of C7. They also lack facets on the transverse processes. It varies by individual, but T10 may resemble the atypical nature of the 11 and 12 vertebrae. When that is the case, T9 lacks an inferior demifacet, as it would not be needed to articulate with the 10th rib.
Additionally, T12 is unique in that it represents a transition from the thoracic to the lumbar vertebra. It is thoracic in that it contains costal facets and superior articular facets that allow for rotation, flexion, and rotation.
It is lumbar in that it has articular processes that do not allow for rotation, only flexion, and extension.
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.
With the aging of the baby-boom generation, employment for chiropractors is expected to increase. Skip to main content. Chapter 6: The Skeletal System. Search for:. The Vertebral Column Learning Objectives Describe each region of the vertebral column and the number of bones in each region Discuss the curves of the vertebral column and how these change after birth Describe 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 Column. Interactive Link Osteoporosis is a common age-related bone disease in which bone density and strength is decreased. General Structure of a Vertebra. Regional Modifications of Vertebrae.
Interactive Link Use this tool to identify the bones, intervertebral discs, and ligaments of the vertebral column. Career Connections: 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.
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