Thoracic Walls

Question 1

What is the area of the base of the breast?

Answer 1

2nd to 6th rib, border of sternum to mid axillary line with a suprolateral extension towards the axilla (axillary tail)

Question 2

In which quadrant of the breast is there a higher incidence of tumor?

Answer 2

The upper outer quadrant - because it has a larger area due to the axillary tail

Question 3

What is the submammary space?

Answer 3

The space between the breast tissue and the underlying muscle

Question 4

What is the arterial supply of the breast?

Answer 4

Arteries come in laterally via the lateral thoracic artery and the lateral cutaneous branches of posterior intercostal arteries and also medially from the internal thoracic artery

Question 5

What is the venous drainage of the breast?

Answer 5

Follows the pattern of the arteries - medial and lateral

Question 6

What is the lymphatic drainage of the breast?

Answer 6

Drains laterally to the axilla (which can be palpated) and medially to the internal thoracic nodes (which can’t be palpated)

Question 7

How many ribs are there?

Answer 7

12 pairs

Question 8

What are the true ribs?

Answer 8

Ribs 1-7 which articulate directly with manubriosternal cartilage

Question 9

What are false ribs?

Answer 9

Ribs 8-10 which articulate with the costocartilage above

Question 10

What are floating ribs?

Answer 10

Ribs 11-12 which don’t articulate anteriorly

Question 11

What is the structure of a typical rib?

Answer 11

Head of the rib has two articular facets, tubercle with two facets (medial is articular and lateral is rough), shaft, groove on inferior margin of internal aspect, pit at the sternal end for costal cartilage

Question 12

Which ribs are atypical?

Answer 12

1,2,11,12

Question 13

What are the 3 significant features of thoracic vertebrae?

Answer 13

demi-facets on the vertebral body, facets on the tips of the transverse processes, long vertical spinous processes

Question 14

What is the costovertebral joint?

Answer 14

The joint between the head of the rib and the demi facets on the vertebral bodies

Question 15

What is the costotransverse joint?

Answer 15

The joint between the tubercle of the rib and the transverse processes of the thoracic vertebrae

Question 16

How is the superior aperture of the thoracic cage reduced in dimension?

Answer 16

By the supra plural membrane - to stop the lungs expanding into the neck

Question 17

What is the origin of the diaphragm?

Answer 17

xiphoid process, costal margin, tips of the 11th and 12th rib, arcuate ligaments (fascia overlying muscles of the posterior wall), left and right crus

Question 18

Which crus is longer?

Answer 18

The right crus (L1-3) - compared with only L1,2 for the left crus

Question 19

What is the insertion of the diaphragm?

Answer 19

The central tendon

Question 20

What are the 3 major apertures in the diaphragm?

Answer 20

caval orifice, oesophageal hiatus and the aorta

Question 21

Where is the caval orifice?

Answer 21

At T8 to the right of the midline

Question 22

Where is the oesophageal hiatus?

Answer 22

At T10 slightly to the left of the midline

Question 23

Where is the aortic hiatus?

Answer 23

At T12 between the crura against the lumbar vertebral column

Question 24

What is the nerve supply of the diaphragm?

Answer 24

The right and left phrenic nerve

Question 25

What are the 3 muscles of the intercostal space?

Answer 25

External, internal and innermost

Question 26

In what direction are the fibres of the external intercostal muscle?

Answer 26

anteroinferior - hands in front pockets

Question 27

What is the action of the external intercostal muscles?

Answer 27

Pulls ribs below up and out to expand the rib cage in inspiration

Question 28

What area of the intercostal space does the external intercostal muscle cover?

Answer 28

The whole space posteriorly, laterally and anteriorly up until it is replaced by the external intercostal membrane

Question 29

In what direction are the fibres of the internal intercostal muscles?

Answer 29

posteroinferior - hands in back pockets

Question 30

What is the action of the internal intercostal muscles?

Answer 30

Pulls ribs down and in

Question 31

What area of the intercostal space does the internal intercostal muscle cover?

Answer 31

The whole space anterior, laterally and posteriorly up until it is replaced by the internal intercostal membrane

Question 32

In what direction are the fibres of the innermost intercostal muscles?

Answer 32

Posteroinferior - hands in back pockets

Question 33

What is the action of the innermost intercostal muscles?

Answer 33

Pulls ribs down and in

Question 34

What area of the intercostal space does the innermost intercostal muscle cover?

Answer 34

Discontinuous - covers some parts but not all - mostly lateral

Question 35

Where is the neuromuscular bundle found in there intercostal space?

Answer 35

In the intercostal groove at the top of the intercostal space between the internal and innermost intercostal muscles

Question 36

In what order are the vessels in the neuromuscular bundle?

Answer 36

Vein, artery, nerve from above down

Question 37

What nerve runs through the intercostal space?

Answer 37

The intercostal nerve - the ventral rams of the spinal nerve - it gives off cutaneous branches laterally and anteriorly

Question 38

What arteries run through the intercostal space?

Answer 38

The posterior intercostal artery (a branch of the thoracic aorta) and the anterior intercostal artery (a branch of the internal thoracic artery)

Question 39

What veins run through the intercostal space?

Answer 39

The anterior intercostal vein (drains into the internal thoracic vein) and posterior intercostal vein (drains into the azygous vein)

Question 40

How does the thoracic cage increase in an antero-posterior direction?

Answer 40

By elevating the upper ribs which pushes the sternum forward

Question 41

How does the thoracic cage increase in the lateral dimension?

Answer 41

By elevating the lower ribs

Question 42

What are some of the accessory muscles of respiration?

Answer 42

sternocleidomastoid, scalenes, abdominals muscles