Module 11: Vertebral Column, Thoracic Cage, and Trunk Wall
Module 11: Vertebral Column, Thoracic Cage, and Trunk Wall
Learning Objectives:
By the end of this module, students will be able to:
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Describe the components of the vertebral column and its regional variations.
- List the bones of the thoracic cavity and their key landmarks.
- Identify and describe the structure and function of the muscles of the thoracic and abdominal walls.
- Identify the neurovascular structures supplying and innervating the abdominal wall.
Terms to Know
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Vertebral Column
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Bones of the Thoracic Cage
Neurovascular Structures
Muscles of the Abdominal Wall
Muscles of the back
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The vertebral column is also known as the spinal column or spine. It consists of a sequence of vertebrae (singular = vertebra), each of which is separated and united by an intervertebral disc. Together, the vertebrae and intervertebral discs form the vertebral column. It is a flexible column that supports the head, neck, and body and allows for their movements. It also protects the spinal cord, which passes down the back through openings in the vertebrae.
Regions of the Vertebral Column
*This content is covered in the pre-lecture assignment and will not be covered again in lecture.
The vertebral column is subdivided into five regions, with the vertebrae in each area named for that region and numbered in descending order. There are seven cervical vertebrae in the neck, 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 the cervical vertebrae 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 by the fusion of five sacral vertebrae. Similarly, the coccyx, or tailbone, results from the fusion of three to four small coccygeal vertebrae. However, the sacral and coccygeal fusions do not start until age 20 and are not completed until middle age.
Fun Fact – Cervical Vertebrae (-> you will not be assessed on this content)
An interesting anatomical fact is that almost all mammals have seven cervical vertebrae, regardless of body size. This means that there are large variations in the size of cervical vertebrae, ranging from the tiny cervical vertebrae of a shrew to the greatly elongated vertebrae in the neck of a giraffe. In a full-grown giraffe, each cervical vertebra is 11 inches tall.
Curvatures of the Vertebral Column
*This content is covered in the pre-lecture assignment and will be elaborated on in lecture.
The adult vertebral column does not form a straight line but instead has four curvatures along its length. 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, the curvatures increase in depth (become more curved) to accommodate the extra weight. They then spri