Thorax Learning Objectives

Question 1

Name the boundaries and general contents of the thoracic cavity, including compartments.

Answer 1

Boundaries: spine, sternum, diaphragm, superior thoracic aperture

Contents: contains primary organs of respiratory and cardiovascular systems

Compartments: right and left pleural cavities (lungs), inferior mediastinum (heart), superior medistinum

Question 2

Describe the components and functions of the thoracic wall.

Answer 2

Components:
Skin, subcut. tissue, ribs, intercostal mm.

Functions:
Protection
Respiration
Muscle attachment

Question 3

Identify the three different types of ribs.

Answer 3

True (direct cartilaginous attachment to sternum)
1st – 7th

False
8th – 10th

Floating
11th & 12th

Question 4

Describe the general structure of a rib.

Answer 4

Body (shaft) of rib
Costal angle
Costal tubercle
Neck of rib
Head of rib

Question 5

Name the three rib joints and give their synovial classification.

Answer 5

Costovertebral
Head of rib → vertebral body

Costotransverse
Costal tubercle → transverse process

Sternocostal
Sternum → costal cartilage

Synovial classification
All are ‘plane’

Question 6

Explain the unique landmarks of the first rib and sternum.

Answer 6

First rib (superior view):
Scalene tubercle
Grooves for the subclavian artery & vein

Sternum:
Manubrium
- Jugular notch
- Clavicular notch/facet

Body

• Sternal angle
• Costal notches/facets

Xiphoid process

Question 7

Describe the action and segmental and peripheral nerve innervation of the diaphragm.

Answer 7

Inferior displacement (becomes flat with contraction)

```
Phrenic nerve (right and left
C3-5)
~~~

Question 8

Describe the naming convention of the intercostal nerves (T1-T12).

Answer 8

Intercostal nn. (T1-6)
Upper intercostal nn.

Thoracoabdominal nn. (T7-11)
(can also be called lower intercostal nn.)

Subcostal n. (T12)

Intercostal nerve = ventral ramus of thoracic spinal nerve

Question 9

Identify the major landmarks of the innervation of the thoracic wall.

Answer 9

T4 includes the nipple

T6 skin over xiphoid

T10 includes the umbilicus

Question 10

Describe the respiratory movement of the thoracic wall.

Answer 10

Increase the volume of the thoracic cavity

Vertical dimension
Depression of the diaphragm

Med/Lat dimension:
Inspiration
- Ribs elevate and move middle of shaft laterally (bucket handle)

Expiration
- Ribs depress and move middle of shaft medially

Ant/post dimension:
Inspiration
- Ribs elevate and move sternum upward and forward (pump handle)

Expiration
- Ribs depress and move sternum downward and backward