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Question 1

Three intercostal muscles

Answer 1

• external (superficial)
• internal
• innermost (deep)

Question 2

Features of the external (superficial) intercostal muscles. (Fibre direction, what do they contract to do?)

Answer 2

• fibre direction (viewed laterally): anteriorly, inferiorly
• contract to lift thoracic cage = inspiration

Question 3

Features of internal and innermost interconstal muscles (fibre direction, what do they contract to do)

Answer 3

• fibre direction (viewed laterally): psoteriorly, inferiorly
• contract to lower thoracic cage = forced expiration

Question 4

What is the nervous innervation of the intercostal space

Answer 4

• innervate by intercostal nerves
• accompany blood vessels (intercostal artery, vein) - all run together
• located between internal and innermost

Question 5

Where do the intercostal nerves branch from

Answer 5

The ventral ramus of spinal nerves

Question 6

What do the intercostal nerves supply?

Answer 6

Intercostal muscles, skin and parietal pleura

Question 7

Vasculature of the intercostal space

Answer 7

• intercostal arteries
• intercostal veins
  (Have an anterior supply, come off anterior blood vessels and move latterly and come off posterior blood vessels and move laterally at each intercostal space?)

ANASTOMOSE LATERALLY

Question 8

Anterior and posterior intercostal arteries - where are they derived from, flow list.

Answer 8

Anterior intercostal artery

Subclacian artery —> internal thoracic artery —-> anterior intercostal artery

Posterior intercostal artery

Thoracic aorta —-> posterior intercostal artery

Question 9

Anterior and posterior intercostal veins, where are they derived from, flow list

Answer 9

Anterior intercostal vein —> internal thoracic vein —> brachiocephalic vein

Posterior intecostal vein —> azygos system (depends on location)

Question 10

What is the azygous system

Answer 10

• anastomotic pathway to drain blood from body wall to superior vena cava

Question 11

What is the azygous system

Answer 11

• anastomotic pathway to drain blood from body wall to superior vena cava

Question 12

Azygous vein?

Answer 12

• manage drainage of the right
• drains into the superior vena cave

Question 13

Hemiazygous vein

Answer 13

Drains the lower half of the left hand side of the posterior thoracic wall
- this then drains into the azygous vein

Question 14

Accessory hemiazygous vein?

Answer 14

Manages drainage on the left of the posterior thoracic cavity
- drains into the azygous vein

Question 15

What is the endothoracic fascia?

Answer 15

• connective tissue (loose) later with variable amounts of adipose
• between intercostal muscles and the parietal pleura

Question 16

Where is the endothoracic fascia

Answer 16

• lines inner wall of thorax, external to pleura
• extends over cupola of the pleura as “suprapleural membrane”
• thin layer between diaphragm and pleura

Question 17

The endothoracic fascia can as as a…

Answer 17

Cleavage plane for surgery

Question 18

Order of structures from skin to visceral pleura

Answer 18

Question 19

3 surgical approaches to the thoracic cavity

Answer 19

1. Intercostal space (lateral approach) “thoracotomy”
   - need to be carpal to not go too far and damage pleura
   - good cos u dont put stability of whole thoricic cavity at risk but likely to hurt nerves and arteries
2. Rib bed (lateral approach) - rib transection “costal resection”
   - cut out some rib
3. Sternum (anterior approach) - sternal transection “sternotomy”
   - split longnatudianlly through the body of the sternum to approach contents of mediastinum

Question 20

The diaphragm fills the…

Answer 20

Thoricic aperture

Question 21

What seperates the thoracic from abdominopelvic cavity

Answer 21

Diaphragm

Question 22

Muscle fibre of the diaphragm

Answer 22

• radiating muscle fibres radiating out of the central tendon

Question 23

Central tendon and the diaphragm has attachments to…

Answer 23

Stentum, costal and lumbar

Question 24

Shape of the diaphragm when relaxed vs contracted

Answer 24

• dome-shapes
• flat

Question 25

Nervous innervation of the diaphragm

Answer 25

Phrenic nerve (comes from 345 cervical spine)

(345 keeps they diapharm alive)

Question 26

Blood supple of the diaphragm

Answer 26

Internal thoracic artery

Question 27

3 apertures of the diaphragm

Answer 27

• aortic hiatus
• vena cabal foramen
• oesophageal hiatus

Question 28

Where is the aortic hiatus and what passes through it?

Answer 28

• T12
• descending aorta, thoracic duct, azygous vein

(Posterior)

Question 29

Where is the vena caval foramen located and what passes through it

Answer 29

• T8
• inferior vena cava

(Medial)

Question 30

What is the oesogeal hiatus and what passes through it

Answer 30

• T10
• oesophagous, vagus nerve

(Interior)

Question 31

Answer 31

Question 32

Process of inspiration

Answer 32

• external intercostal muscles contract
• rib cage rises and expands
• diaphragm contracts to become flattened
• thoracic cavity volume increases
• lungs stretch
• lung (intrapulmonary) volume goes up
• intrapulmonary pressure goes down
• airflows down the pressure gradient moving into the lungs

Question 33

What happens during expiration

Answer 33

• external intercostal muscles relax (Internal intercostal muscles contract during forced expiration only)
• rib cage descends and reduces
• diaphragm relaxes and rises, becomes dome-shaped
• lungs recoil and thoracic cavity volume decreases
• lung (intrapulmonary) volume goes down and intrapulmonary pressure goes up
• air flows down the pressure gradient, which is now higher inside than out, so air moves out of the lungs

Question 34

What happens during expiration

Answer 34

• external intercostal muscles relax (Internal intercostal muscles contract during forced expiration only)
• rib cage descends and reduces
• diaphragm relaxes and rises, becomes dome-shaped
• lungs recoil and thoracic cavity volume decreases
• lung (intrapulmonary) volume goes down and intrapulmonary pressure goes up
• air flows down the pressure gradient, which is now higher inside than out, so air moves out of the lungs

Question 35