The pulmonary or respiratory system (Figure 10-1) consists of the sternum, 12 pairs of ribs, the clavicle, and the vertebrae of the thoracic spine, which form the thoracic cage (Table 10-1).
Schematic representation of the main divisions of the respiratory tract. (Reproduced, with permission, from Junqueira LC, Carneiro J: Basic Histology: Text and Atlas, 10th ed. New York: McGraw-Hill. 2003:349.)
Table 10-1. Bony Anatomy of the Thoracic Cage ||Download (.pdf)
Table 10-1. Bony Anatomy of the Thoracic Cage
Consists of three parts: the manubrium, the body, and the xiphoid process.
The articulation between the manubrium and the sternum serves to allow the pump-handle action of the sternal body during respiration.
The Rib cage
Formed by twelve pairs of ribs, each different from the others in size, width, and curvature, although they share some common characteristics.
- Ribs 1-7 are considered to be true ribs and have a single anterior costochondral attachment to the sternum. Approximately 32 structures attach to the first rib and body of T1.
- Ribs 8-10 are referred to as false ribs as they share costochondral attachments before attaching anteriorly to the sternum.
- Ribs 11 and 12 are termed floating or costovertebral ribs as they have no anterior attachment with the sternum.
Based on the orientation of the joint axes of the thoracic vertebrae, movement of the upper ribs is primarily in an anterior and posterior direction (pump handle), whereas the transverse diameter increases for the lower ribs allowing movement primarily in the medial-lateral direction (bucket handle).
Forms an intimate relationship between the head of the rib and the lateral side of the vertebral body.
- The first, 11th, and 12th ribs articulate fully with their own vertebrae via a single costal facet, without any contact with the intervertebral disk (IVD).
- The remaining ribs articulate with both their own vertebra and the vertebra above, as well as to the IVD.
- External respiration: the exchange of gases between the atmosphere and the blood.
- Internal respiration: the exchange of gases between the blood and the cells of the body.
The primary function of the respiratory system is to exchange gases between the environment and the tissues and blood so that arterial blood oxygen (O2), carbon dioxide (CO2), and pH levels remain within defined limits throughout many different physiological confines.1 In addition, the pulmonary system contributes to temperature homeostasis via evaporative heat loss from the lungs, and protects the remainder of the respiratory system from ...