1. © 2015 Pearson Education, Inc.
The Bony Thorax
Forms a cage to protect major organs
Consists of three parts
Sternum
Ribs
True ribs (pairs 1–7)
False ribs (pairs 8–12)
Floating ribs (pairs 11–12)
Thoracic vertebrae
© 2015 Pearson Education, Inc.

2. Sternum Also called “breastbone” Comprised of 3 bones:
Manubrium
Body
Xiphoid process
Jugular notch – upper border of the manubrium

3. Ribs There are 12 rib pairs
All of them articulate posteriorly with the thoracic vertebrae
The ribs are arranged accordingly:
7 pairs called true ribs- attach directly to the sternum via costal (hyaline) cartilage
5 pairs called false or floating:
3 pairs attach indirectly to sternum
2 pairs float as they aren’t attached to sternum at all

4. Figure 5.22a The bony thorax (thoracic cage).
T1 vertebra
Jugular notch
Clavicular notch
Manubrium
Sternal angle
Body
Sternum
Xiphisternal joint
True ribs (1–7)
Xiphoid process
False ribs (8–12)
Intercostal
spaces
L1 vertebra
Costal cartilage
Floating ribs (11, 12)
(a)

5. Figure 5.22b The bony thorax (thoracic cage).
Jugular notch T3 T4
Sternal angle
Heart
Xiphisternal joint T9
(b)