1. Unit 16: Abdomen & Thoracic Injuries
Lesson 2: Anatomy of the Thorax

2. Objective:
Recognize relevant anatomy of the thorax

3. Terminology Atrium: Intercostal Thorax Ventricle
The upper chambers of the heart
Intercostal
refers to the area between the ribs
Thorax
the chest; the part of the body located between the neck and the abdomen
Ventricle
lower chamber of the heart

4. Terms in Pictures
Atrium
Intercostal
Thorax
Ventricle

5. Thoracic Cavity Boarders
Superior
Clavicle
Inferior
Diaphragm
Anterior
Sternum, ribs and intercostal muscles
Posterior
Spine, ribs, scapulae & erector spinae muscle

6. Rib Cage Anatomy 12 pairs of ribs
True ribs (first 7 pairs): attach directly to the sternum by individual cartilage
False ribs (next 3 pairs): attach indirectly to the sternum by shared cartilage
Floating ribs (next 2 pairs): have no attachment to the sternum

7. Organs of the Thoracic Cavity
Esophagus
Trachea
Lungs
Heart

8. The Esophagus Location: In the throat, behind the trachea
Function: Structure for food to pass from the mouth to the stomach

9. Location: Function: The Trachea
A cartilage structure in the throat, directly in front of the esophagus
The trachea divides into 2 branches (bronchi) which enter the lungs
Function:
Allows air to pass into and out of the lungs

10. Location: Functions: The Lungs Exchange carbon dioxide for oxygen
On either side of the heart
Functions:
Exchange carbon dioxide for oxygen
Help to remove heat from the body

11. Location: Function: The heart
Under the sternum (slightly to the left) and between the lungs
Function:
to pump blood throughout the body
Blood carries oxygen and nutrients to the cells
Blood carries carbon dioxide and waste products away from the cells

12. The Heart Divided into 4 chambers
R and L atrium (upper chambers)
R and L ventricles (lower chambers)
Heart valves separate each chamber and prevent a backflow of the blood
Tricuspid valve
Biscuspid (mitral) valve
Pulmonary valve
Aortic valve

13. Direction blood pumps through the heart

14. How does the blood flow through the Heart?
Left Side of Heart
Right Side of Heart
The pulmonary veins empty oxygen-rich blood from the lungs into the left atrium of the heart.
As the atrium contracts, blood flows from your left atrium into your left ventricle through the open mitral valve.
When the ventricle is full, the mitral valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts.
As the ventricle contracts, blood leaves the heart through the aortic valve, into the aorta and to the body.
Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart.
As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve.
When the ventricle is full, the tricuspid valve shuts. This prevents blood from flowing backward into the atria while the ventricle contracts.
As the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs, where it is oxygenated and then returns to the left atrium through the pulmonary veins.

15. How blood flows through the lungs
Once blood travels through the pulmonic valve, it enters your lungs. This is called the pulmonary circulation. From your pulmonic valve, blood travels to the pulmonary artery to tiny capillary vessels in the lungs.
Here, oxygen travels from the tiny air sacs in the lungs, through the walls of the capillaries, into the blood. At the same time, carbon dioxide, a waste product of metabolism, passes from the blood into the air sacs. Carbon dioxide leaves the body when you exhale. Once the blood is purified and oxygenated, it travels back to the left atrium through the pulmonary veins.