The Thorax

Question 1

True ribs

Answer 1

Ribs 1-7

Costal cartilages articulate directly with the sternum

Question 2

False ribs

Answer 2

8-12

Either articulate anteriorly with the costal cartilages of the ribs above, or do not articulate at all

Question 3

Floating ribs

Answer 3

11 and 12

Much shorter

Question 4

Sternal angle

Answer 4

Separates the manubrium and ht body of the sternum
Easily palpated
marks articulation of rib 2 with the sternum, therefore a grid reference for counting ribs§

Question 5

External intercostal muscle

Answer 5

Muscle fibres directed downwards and forwards
“hands in pockets”
Contract upon inhalation, aiding in raising of the chest

Question 6

Internal intercostal muscle

Answer 6

Lie in opposite directions to the external fibres
“Hands on chest”
Contract upon forced exhalation

Question 7

neurovascular bundle

Answer 7

Consists of the intercostal vein, artery and nerve

Lies between internal and innermost intercostal muscles

Question 8

Inserting needle into intercostal space

Answer 8

Place in lower part because this avoids the neuromuscular bundle which is present at the lower border of the ribs

Question 9

Intercostal nerves

Answer 9

Anterior rami of the first 11 thoracic nerves, supply the intercostal muscles, chest wall skin and the parietal pleura

Question 10

Internal thoracic artery

Answer 10

Major artery on the anterior aspect of the chest wall
branch of the subclavian artery
Lies 1cm lateral to the sternum

Question 11

Anterior intercostal arteries

Answer 11

Branches of the internal thoracic artery or those of it’s musculophrenic branch
Posterior intercostal arteries derived from the descending thoracic artery

Question 12

Anastomes

Answer 12

Between anterior and posterior intercostal arteries

Important collateral channels for circulation incases of blood flow in the aorta

Question 13

Lungs and pleural cavities

Answer 13

Thoracic cavity subdivided into left and right pleural cavities, each surrounding a lung, and the mediastinum
Problems in one pleural cavity does not necessarily effect the other
Also mediastinum can be entered surgically without opening the pleural cavities

Question 14

The pleural cavity

Answer 14

Potential space between two layers of pleura
Outer parietal layer of pleura lines the thoracic cavity and inner visceral or pulmonary layer closely fits onto lung surface
Two layers become continuous at the root of the lung

Question 15

Right lung

Answer 15

Subdivided into superior, middle and inferior lobes by an oblique and horizontal fissure

Question 16

Horizontal right lung fissure

Answer 16

Fourth rib

Question 17

Oblique fissure of the lungs

Answer 17

Second thoracic vertebrae

Question 18

Left lung

Answer 18

Divided into superior and inferior lobes with an oblique fissure between
Depression behind due to aortic arch

Question 19

Lung hilum

Answer 19

Where the arteries, veins and bronchus lie

Enclosed in a sleeve of pleura which loosely hangs down in its lower part as the pulmonary ligament

Question 20

Root of the lung

Answer 20

Contains bronchial arteries supplying bronchi and bronchioles, the pulmonary plexus of autonomic nerves innervating the nerves and lymph nodes draining it

Question 21

Phrenic nerve

Answer 21

Lies in front of the root of the lung and vagus nerve behind

Question 22

Right bronchus

Answer 22

Shorter wide and more vertical

Question 23

Angle between he two bronchi

Answer 23

70 in an adult
25 to right
45 to left
Foreign bodies more likely to go in right

Question 24

Superior mediastinum

Answer 24

Demarcated by a horizontal plane that passes through the body of the 4th thoracic vertebra and manubrio-sternak joint
This level - arch of aorta gives off the brachiocephalic trunk, the left common carotid and the left subclavian artery

Question 25

Lying anterior to the great vessels

Answer 25

The jugular and subclavian veins that converge on the left to form the brachiocephalic vein before merging with the jugular vein on the right to form the superior vena cava

Question 26

Trachea in mediastinum

Answer 26

and upper part of the thoracic oesophagus posterior to greta vessels Trachea passes into posterior mediastinum

Question 27

Division of the trachea

Answer 27

occurs at the 4th thoracic vertebra | oesophagus lies behind

Question 28

vagus nerve

Answer 28

Enters chest from the neck close to the sides of the trachea and oesophagus Goes on to supply the organs of the chest before penetrating the diaphragm to supply much of the abdominal viscera

Question 29

Phrenic nerve

Answer 29

Lies lateral to the vagus Arises from the neck passes in front of the root of each lung Goes on to supply the pericardium and muscles of the diaphragm

Question 30

thoracic diaphragm

Answer 30

Chest is bound by ribcage laterally and diphragm interiorly Separates diaphragm from the abdomen Pierced by oesophagus and IVC Innervated by the phrenic nerve

Question 31

Four corners of the heart

Answer 31

1 - 3rd costal cartilage, 1 finger-length to edge of sternum 2 - 6th costal cartilage, edge of sternum 3 - 2nd intercostal space, one finger-width lateral to the sternum 4 - 5th intercostal space, midclavicular line

Question 32

Heart significance of T4/5

Answer 32

Top of heart, where vessels begin and sternal angle position

Question 33

inter ventricular arrert

Answer 33

Supplies the anterolateral myocardium, apex and inter ventricular septum Typically supplies 50% of the left ventricle

Question 34

Circumflex artery

Answer 34

Supplies the posterolateral left ventricle and also the SAN in 38% of perople

Question 35

Right coronary artery

Answer 35

Supplies mainly the right atrium and ventricle

Question 36

Left coronary artery

Answer 36

Supplies the left atrium and ventricle

Question 37

marginal artery

Answer 37

Supplies all the surface of the right ventricle

Question 38

Posterior inter ventricular artery

Answer 38

Supplies the posterior intraventricular septum

Question 39

Crista terminalis

Answer 39

In left atrium | Smooth and rough part separated by this vertical ridge

Question 40

Foremen ovale

Answer 40

Only present in the foetus In fetes it allows blood to flow from the right to the left atrium, bypassing the lungs Pressure changes at birth so the foramen oval closes and the fossa ovals forms

Question 41

Fossa ovalis

Answer 41

Oval depression on the intertribal wall

Question 42

Trabecular carnae

Answer 42

Muscular ridges on the anterior of the ventricle

Question 43

Papillary muscles

Answer 43

Attach to the valves

Question 44

Chordae tendinae

Answer 44

Connect papillary muscles to the tricuspid valve cusps Prevent the valve cusps being everted into atrium 80% collagen dn 20% elastin

Question 45

Aortic sinus

Answer 45

Coronary arteries originate from the sinuses | Right from anterior and left from posterior aortic sinus

Question 46

Interventriculae septum

Answer 46

Has the muscular and membranous parts Bulges into right ventricle Separates the ventricles Contributes to the pumping action of left ventricle

Question 47

SA node

Answer 47

Hearts pacemaker | Situated in the right atrium at upper end of the crista terminalis

Question 48

AV node

Answer 48

Situated in the interatrial septum near the opening of the coronary sinus

Question 49

Coronary artery dominance

Answer 49

Depends on which artery supplies the AV node | R - 70%, L - 15%, Co - 15%

Question 50

Ligamentum arteriosum

Answer 50

Remnant of ductus arterioles Connected the pulmonary artery and the aorta in the fetus Stops blood passing through the lungs