Video Transcript
What are the components of the
thoracic cage? (A) 10 thoracic vertebrae and the
sternum. (B) 12 thoracic vertebrae, 12 pairs
of ribs, and the sternum. (C) Six thoracic vertebrae, six
lumbar vertebrae, and the spinal cord. Or (D) 12 pairs of ribs, the
sternum, and a thoracic vertebra.
This question focuses on the axial
skeleton, which is made up of the skull, the thoracic or rib cage, and the vertebral
or spinal column. The question specifically asks
about the thoracic cage. However, to understand the thoracic
cage, we must first look at the vertebral column.
The vertebral column is made up of
individual vertebrae separated by cartilage in a long, vertical chain. There are five main parts: the
cervical vertebrae, the thoracic vertebrae, the lumbar vertebrae, the sacral
vertebrae, and the coccygeal vertebrae, with the sacral and coccygeal vertebrae
being fused together. The vertebral column protects the
spinal cord and provides stability and movement.
It’s important to understand the
vertebral column when looking at the thoracic cage because the thoracic vertebrae
are considered to be both part of the vertebral column and the thoracic cage. There are 12 thoracic vertebrae and
12 corresponding pairs of rib bones, as shown here. The top 10 pairs of ribs all meet
in a structure called the sternum, or breastbone, at the front. The rib cage provides attachment
sites for lots of muscles, including the diaphragm, and protects many of our
internal organs, such as the heart and lungs.
Using this information, we can
deduce that the correct answer is (B). The thoracic cage consists of 12
thoracic vertebrae, 12 pairs of ribs, and the sternum.
