Lecture 3

Question 1

What makes up the sternum?

Answer 1

Manubrium, sternum proper and xiphisternum.

Question 2

Describe the manubrium?

Answer 2

Articulates with ribs 1+2 laterally and has a jugular notch on the top, and it is a small and flat bone.

Question 3

Describe the sternum proper?

Answer 3

It articulates with majority of the ribs and is inferior to the manubrium.

Question 4

Describe the Xiphisternum?

Answer 4

It is the inferior part of the sternum.

Question 5

What is the angle of louis?

Answer 5

Slight angle between manubrium and sternum proper. It is convex, so it sticks out. It is an important landmark, as you look at the jugular vein relative to the angle of louis. It is where you start counting ribs from.

Question 6

What is the angle of louis in line with?

Answer 6

Rib 2. Start counting at rib 2 and count down.

Question 7

How many ribs are there?

Answer 7

12.

Question 8

What are true ribs?

Answer 8

First ribs 1-7. Start articulating with the spinal column t the back and articulate directly with the sternum at the front via costal cartilages.

Question 9

What are false ribs?

Answer 9

Ribs 8-10. Attach all together via the costal cartilages.

Question 10

What are floating ribs?

Answer 10

Ribs 11-12. No anterior attachment.

Question 11

What are the ribs most likely to be broken?

Answer 11

Ribs that are in the mid portion, where they don’t have a lot of give and attach directly into the sternum. You actually dislocate the rib and the costal cartilage off the sternum.

Question 12

What do the ribs articulate with?

Answer 12

Each rib has its own vertebra and the one above.

Question 13

What numbers do you use when talking about ribs?

Answer 13

Roman numerals.

Question 14

What is posterior of the rib?

Answer 14

Head of the rib which articulates with the vertebral column.

Question 15

What is the costal groove?

Answer 15

Where the neurovascular bundle sits. Allowing the bundle to be protected by the ribs.

Question 16

What does the sternum do?

Answer 16

Lift up and have a superior movement lifting forward, where as the ribs ahem a bucket handle motion. As you breath in, they lift up the sides.

Question 17

What is the Superior Thoracic Aperture?

Answer 17

Thoracic Inlet.

Question 18

What is the thoracic inlet bounded by?

Answer 18

Posterior = T1.
Anterior = Manubrium.
Laterally = Rib 1.

Question 19

Why are the ribs sloped?

Answer 19

As the ribs come off the vertebral column posteriorly and laterally they slope down a lot.

Question 20

Why is it important that the ribs are sloped?

Answer 20

The uppermost portion of the pleura extends above the level of the first rib. Within the region of no cover, the lung cavity is at risk. Be aware of chance of pneumothorax in this region.

Question 21

What is the Inferior Thoracic Aperture?

Answer 21

Thoracic outlet.

Question 22

What is the thoracic outlet bounded by?

Answer 22

Diaphragm.

T12, Rib 12 and costal cartilages of the false ribs.

Question 23

What is the diaphragm consist of?

Answer 23

Two domes. A lot of the abdominal content is protected by the ribs - liver and spleen.

Question 24

What are the muscles between the ribs?

Answer 24

External Intercostal.
Internal Intercostal.
Innermost Intercostal.

Question 25

How do the fibres run for the intercostal muscles?

Answer 25

External = infero-medial.

Internal and innermost = supero-medial.

Question 26

Where does the neurovascular plane run?

Answer 26

Between Internal and innermost intercostal muscles.

Question 27

What do the intercostal muscles do?

Answer 27

Stiffen the chest wall, and give the diaphragm something to pull against.

Question 28

Describe the neurovascular bundle?

Answer 28

From superior to inferior:

Vein, artery and nerve. They run in the costal groove in the rib - allowing them to be protected.

Question 29

Describe the collateral branches?

Answer 29

Not protected as they sit down in the space.

Question 30

Where do the intercostal nerves come from?

Answer 30

The anterior rami of the spinal nerves. Comes out laterally and runs around to the front, it gives off branches which supply the muscles and sensory branches which supply the skin.

Question 31

Describe the dermatomes in the thoracic region?

Answer 31

T4 - nipple line (males, children and vary in adult females).
T10 - umbilicus.

Question 32

Describe the arterial tree for the intercostal space?

Answer 32

Posteriorly - come from aorta.
Anteriorly - Internal thoracic.

From the aorta there are three distinct branches. The first branch is the brachiocephalic trunk on the RHS, the second branch is the left common carotid (heads up into the neck) and the left subclavian (into upper limb). The aorta will continue down as the thoracic aorta. The brachiocephalic trunk will split into two branches: the right common carotid and right subclavian. As the thoracic aorta descends through the thorax, it gives off pairs of arteries into each intercostal space = posterior intercostal arteries. The subclavian arteries will drop off an artery each which come into the anterior chest wall = internal thoracic arteries. The internal thoracic arteries sit close to the sternum, and give off pairs of intercostal arteries = anterior intercostal arteries. The internal thoracic arteries continue to run down and give off the musculo-phrenic arteries and superior epigastric.

Question 33

Describe the venous drainage>

Answer 33

The anterior intercostal veins drain into the internal thoracic vein which drains into the brachiocephalic veins and back into the heart.
The posterior intercostal veins drain into the azygos system (three azygos veins work as one system).

Question 34

What is the breast tissue?

Answer 34

Is a collection of secretory lobules, lactiferous ducts and fat.

Question 35

Where does the breast tissue sit?

Answer 35

Anterior to the thoracic wall and the muscles of the anterior thoracic wall - pec major and serratus anterior.

Question 36

What is posterior to the breast?

Answer 36

Retromammary space - fascia. It moves freely, when there is a breast tumour, once it invades in the space it glues the breast down hard.

Question 37

Describe the arterial supply of the breast?

Answer 37

Medially = branches of internal thoracic artery.  
Laterally = axillary artery i.e. lateral thoracic.  
Directly = intercostal arteries.

Question 38

Describe the axillary process?

Answer 38

Extension of the breast tissue which extends into the tail of the axilla. Tumour or growth can hide in here.

Question 39

Describe the lymphatic drainage of the breast?

Answer 39

75% = laterally into the axillary nodes. 
Rest = medially into the parasternal nodes, which run up and down the sternum, and can cross the midline onto the other side.

Question 40

What is a sentinel node biopsy?

Answer 40

Where you inject dye into the tumour, this will allow you to know where it has metastasised to. Look at the different groups of lymph nodes and which ones have taken up the dye - where tumour has drained to.

Question 41

What is the nerve supply of the breast?

Answer 41

Intercostal nerves:

T5-6.

Question 42

What is Pectus Exuvatum?

Answer 42

A deformity of the sternum and costal cartilages where the chest has sunken in.
Problems with breathing.
Associated with congenital abnormalities.

Question 43

What is Pectus Carinatum?

Answer 43

Pigeon chest, where there the sternum will protrude. Likely to be asymmetrical.

Question 44

What is Kyphosis?

Answer 44

Increased curvature of thoracic spine.

Question 45

What is lordosis?

Answer 45

Increased curvature of the lumbar spine.

Question 46

What is scoliosis?

Answer 46

Curvature in the coronal plane. Rotational deformities.