Component parts

Question 1

3 Main functions of the thorax

Answer 1

• Breathing: contains the lungs and the machinery (diaphragm, thoracic wall and ribs)
• Protection of vital organs: Heart, lungs and great vessels
• Conduit: Mediastinum acts as conduit for structures passing through thorax completely and for structures that connect organs in the thorax to other body regions.

Question 2

The Thoracic wall

Answer 2

This consists of skeletal elements and muscles.

• 12 thoracic vertebrae
• 12 ribs each side
• 3 layers flat muscles
• Sternum (manubrium, body and xiphoid process)

Question 3

What is a true rib

Answer 3

This is ribs 1-7

Their costal cartridges all attach directly to the sternum

Question 4

What is a false rib

Answer 4

Ribs 8-10

Their costal cartridges are indirectly attached to the sternum.

Question 5

Floating rib

Answer 5

They do not articulate with other ribs, costal cartridges or the sternum.

Question 6

Superior thoracic aperture

Answer 6

Completely surrounded by skeletal elements.

- Consists of the body of vertebra TI posteriorly, medial margin of rib I each side and manubrium anteriorly.

Question 7

Inferior Thoracic aperture

Answer 7

It is large and expandable
- bone, cartilage and ligaments form its margin.
Closed by diaphragm and structures passing between abdomen and thorax pierce or pass posteriorly to the diaphragm.

Question 8

As the diaphragm contracts…

Answer 8

The height of the domes decreases and the volume of the thorax increases.
The oesophagus and inferior vena cava penetrate the diaphragm; the aorta passes posterior too the diaphragm.

Question 9

Middle Mediastinum

Answer 9

Pericardium and heart

Question 10

Anterior Mediastinum

Answer 10

Lies between the sternum and the pericardium.

Question 11

Posterior Mediastinum

Answer 11

Lies between the pericardium and thoracic vertebrae

Question 12

Axillary inlet formed by:

Answer 12

• Superior margin of the scapula posteriorly
• The clavicle anteriorly
• The lateral margin of rib I medially.

Question 13

3 parts of the sternum

Answer 13

Manubrium = forms part of the bony framework of the neck and thorax.
body of the sternum = Flat
Xiphoid Process = smallest part

Question 14

Costotransverse joints

Answer 14

Synovial joints between the tubercle of rib and the transverse process of the related vertebra.

Question 15

Intercostal muscles

Answer 15

Three flat muscles found in each intercostal space that. pass between adjacent ribs. external, internal and innermost.