Chapter 9 The respiratory system
Anatomy
1. The bony components of the thorax articulate with one another in such a way as to provide a rigid, yet slightly mobile thoracic cage.
2. It is the articulation of the rib with the vertebral column posteriorly and with the sternum anteriorly, which provides the mobility necessary during respiration.
3. By the action of the muscles, the ribs are moved so as to change the anteroposterior and transverse diameters of the thorax.
Bony Landmarks to be Palpated
Spinous processes in the thoracic region, thoracic transverse processes, ribs, manubrium, sternum and xiphoid process.
Joints of the Thorax (from anterior to posterior)
Sternal joints
Manubriosternal joint:
2. It is an articulation between the inferior surface of the manubrium and the upper surface of the body of the sternum.
3. The opposing surfaces of the two bones are covered with a thin layer of hyaline cartilage, between which there is a fibrocartilaginous disc.
4. A small amount of movement (7°) is permitted at this joint. During inspiration there is a decrease in the obtuse angle between the manubrium and the body of the sternum.
Sternocostal joints
1. These are joints between the medial end of the costal cartilage of the 1st to 7th ribs and the sternum.
Ligaments
| Ligaments | Origin | Insertion |
|---|---|---|
| The anterior radiate ligament | From the medial end of the costal cartilage | Three bands insert into the anterior aspect of the sternum, passing upwards, horizontally and inferiorly |
| The posterior radiate ligament | From the medial end of the costal cartilage | Three bands insert into the posterior aspect of the sternum, passing upwards, horizontally |
