Thorax prosection book

Question 1

Surface markings of the heart

Answer 1

1. Lower border of the third costal cartilage at the right edge of sternum
2. Lower border sixth costal cartilage at right of sternum
3. 5th space in mid-clavicular line
4. Second space, 2cm to left of sternum

Draw a slightly curved line between those 4 points

Question 2

What are the surface markings of the tracheal carina?

Answer 2

Trachea bifurcates into left and right main bronchi just below level of manubriosternal junction

Question 3

What are the landmarks for inserting a chest drain?

Answer 3

-4th intercostal space anterior axillary line, just superior to 5th rib (avoids damaging intercostal vessels that run in upper part of intercostal space, just inferior to corresponding rib)

Question 4

In which layer of chest wall do intercostal vessels run? In what order do they run?

Answer 4

-Run in plane between internal intercostal and innermost intercostal
-Order of: vein–> artery–> nerve from superior to inferior

Question 5

What are the layers of the chest wall?

Answer 5

Can be divided into 3 layers, similarly to abdominal wall

1. External intercostals, serratus posterior superior and inferior
2. Internal intercostals:
3. transversus thoracis (anteriorly, subcostals (posteriorly), and innermost intercostals (laterally

Question 6

In which direction are external and internal intercostals orientated?

Answer 6

External: inferomedial
internal: superomedial (same as internal olique)

Question 7

What are the reflections (and therefore surface markings) of the parietal pleura?

Answer 7

2, 4, 6, 8, 10, 12 rule

-Sarts 2.5cm above midpoint of medial 1/3rd clavicle
-Meets in midline at rib 2
-Left side diverges at rib 4 (to make room for heart)
-Right side continues parasternally to rib 6
-Both cross rib 8 in midclavicular line
-Both cross rib 10 in midaxillary line
-Both reach posterior chest just below rib 12

Question 8

What are the surface markings of the lungs?

Answer 8

-Below rib 6, lungs extend to two rib spaces less than pleura (e.g. opposite to rib 6 mid-clavicular line, rib 8 mid-axillary line, rib 10 inferiorly)
-parietal pleura extends further two rib spaces inferiorly tan the inferior lung edge to allow space for lung expansion
-Note how right and left reflections are not identical: on left, displaced by central position of heart

Question 9

Is there anywhere that pleural cavity is not protected by ribcage?

Answer 9

-Pleural cavity externds above upper border first rib anteirorly
-Posteriorly pleural cavity extends below lower border of 12th rib for a short distance on either side of midline

Question 10

Describe the anatomy of the breast parenchyma

Answer 10

-Breast is composed of gland and duct tissue, with intervening fat
-Terminal duct lobular units produce milk
-These drain into approximately 10-20 lactiferous ducts that converge on nipple
-Glandular breast is supported by fibrous septae known as suspensory ligaments of astley cooper

Question 11

What is the nerve supply of breast skin?

Answer 11

=Supraclavicular branches cervical plexus
-Intercostal nerves
-Intercostobrachial nerve

Question 12

What is nerve supply of nipple?

Answer 12

4th intercostal nerve

Question 13

The breast is a modified type of which common kind of skin gland?

Answer 13

Modified apocrine sweat gland

Question 14

What movements do the ribs make during inspiration?

Answer 14

-Bucket handle and pump handle movement
-Bucket handle: increases transverse diameter of chest
-Pump handle: increases anteroposterior diameter of chest

Bucket handle movement:
–> contraction of intercostal muscles causes middle of ribs to move upwards
–> increases transverse diameter of the chest

Pump handle movement
–> Posterior rib is higher than anterior rib
–> therefore movement at costovertebral joint also causes anterior rib to move upwards
–> increases anteroposterior diameter of chest