The thoracic cage, or rib cage, is a structure that safeguards the heart, lungs, and other organs within the chest cavity. It is composed of 12 pairs of ribs, 12 thoracic vertebrae, and the sternum (breastbone), forming a strong yet flexible enclosure. The ribs attach to the thoracic spine in the back and extend around the sides of the torso toward the front, expanding and contracting with breathing.
The 7th Rib’s Classification
The 7th rib belongs to a group known as the “true ribs,” which includes the first seven pairs of ribs. This classification is determined by how the rib connects to the sternum at the front of the chest. True ribs are unique because they each possess their own piece of costal cartilage, which is a specialized type of flexible connective tissue.
This individual strip of cartilage extends from the end of the bony rib and forms a direct, separate attachment point to the sternum. The 7th rib is the final pair in this group that maintains this independent connection, providing stability to the upper part of the rib cage. The ribs below the seventh have indirect or no connection to the breastbone.
Specific Anatomical Attachments
The 7th rib curves from the spine in the back toward the sternum in the front. Its posterior end articulates with the seventh thoracic vertebra (T7). The head of the rib connects to the body of the T7 vertebra and partially to the body of the T6 vertebra above it.
The rib’s anterior connection is made by its costal cartilage, which joins the body of the sternum. This attachment point is situated inferior to the ribs above it, connecting to the lower portion of the sternal body. The 7th rib is often the lowest rib that articulates directly with the breastbone.
How to Locate the 7th Rib
Locating the 7th rib involves using surface anatomy landmarks, which are palpable points felt through the skin. A reliable starting point is the sternal angle, a slight horizontal ridge on the sternum where the upper and lower parts of the breastbone meet. This angle is directly adjacent to the cartilage of the second rib. Once the second rib is identified, place your fingers in the space directly below it (the second intercostal space), and count down sequentially to the seventh rib. The 7th rib is the last one whose cartilage connects directly to the sternum before the ribs start joining the costal margin.