The Thorax (2) Flashcards
State the boundaries of the upper thorax.
The thoracic inlet is named the superior thoracic aperture. It is bound by the vertebra of T1 and the 1st rib.
State the boundaries of the lower thorax.
The thoracic outlet is named the inferior thoracic aperture. It is bound by ribs 7 to 12, T12 and the xiphoid process.
State the functions of the thoracic wall.
Respiration (intrinsic/extrinsic muscles), protects organs, supports the breast.
What is the thoracic wall?
The thoracic wall is the muscles and bones enclosing the thoracic cavity.
What is endothoracic fascia?
The endothoracic fascia is loose connective tissue that separates the ribs from underlying fascia.
Describe the composition of the endothoracic fascia.
It contains various amounts of fat. It thickens over the top of each lung as suprapleural (Sibson’s) fascia. This Sibson’s fascia attaches to the internal border of the 1st rib and the TP of C7.
Label the diagram
1=neck
2=head
3=superior facet
4=crest of head
5=inferior facet
6,7=site of articulation with costal cartilage
8=internal surface
9=external surface
10=costal groove
11=body/shaft
12=costal angle
13=non-articular part
14=articular facet
15=tubercle
The 1st rib has an extra tubercle, name it and its location. What neurovascular structures lie next to it?
Scalene tubercle, medial to the regular tubercle. Medially lies the subclavian vein, laterally lies the subclavian artery.
State the sex differences in the anatomy of the sternum.
The sternum is shorter in females.
State the sex differences in the anatomy of the thoracic inlet.
The thoracic inlet is more oblique in females.
State the sex differences in the anatomy of the suprasternal (jugular) notch.
It is at the level of T2 in males and T3 in females.
State the anterior thoracic lines.
The anterior median line (down the middle) and the midclavicular lines (passing through the midpoint of either clavicle).
State the lateral thoracic lines.
The anterior, posterior and mid axillary line
State the posterior thoracic lines.
The midvertebral line and the right and left scapular lines (passing the inferior angle of the scapulae).
What does the infrasternal angle describe.
The infrasternal angle, localised at the xiphoid process, is the angle between the costal margins.
At what level is the sternal angle (the manubriosternal junction)?
The sternal angle is the point of junction of the 2 costal cartilage (T4/5).
What major vein passes behind the manubrium?
The superior vena cava
What is auscultation?
Auscultation is the act of listening to internal body sounds.
Label the diagram.
C=aortic valve
D=pulmonary valve
E=tricuspid valve
F=mitral valve (male)
G=mitral valve (female)
What is interchondral subluxation.
Interchondral subluxation is the dislodgement of the rib from the interchondral joint.
Explain the abbreviation RIPE, in relation to chest X-rays.
RIPE is used to evaluate the quality of a chest X-ray image.
Rotation-ensure the patient isn’t rotated-by ensuring that each medial clavicle is equidistant from the spinous process.
Inspiration-inspiration must be of an adequate level-apices, costophrenic angles and 5-6 anterior ribs should be visible.
Penetration/Exposure-ensure there is appropriate exposure in the image-vertebrae must be just visible behind the heart (AP).
Explain the abbreviation ABCDDE, in relation to chest X-rays.
ABCDDE is a systematic approach to interpreting chest X-rays.
Airways-trachea, bronchi, carina
Breathing-lungs, apices, costophrenic angle
Circulation-heart size, mediastinum
Diaphragm-right hemidiaphragm ought to be higher than the left
Disability-fractures, deformities
Everything else-tubes, pacemakers, foreign objects, sub-diaphragmatic free air(indicates perforation of a hollow abdominal organ)
Label this diagram of a PA chest X-ray.
1=right apex
2=spinous process
3=trachea
4=carina
5=right hilum
6=right cardiac border
7=vertebral body
8=right hemidiaphragm
9=right costophrenic angle
10=1st anterior rib
11=left clavicle
12= posterior rib
13=aortic knuckle
14=left hilum
15=left cardiac border
16=gastric bubble
17=left costophrenic angle
State the pathophysiology, symptoms and treatment of tension pneumothorax.
Pathophysiology: air builds up in the pleural space, causing lung collapse on the affected side. Increased intrathoracic pressure compresses heart, mediastinum and contralateral lung.
Symptoms: shortness of breath (absent breath sounds on affected side), cyanosis, hypotension, tachycardia, distended neck veins, hyper resonant percussion due to air.
Treatment: immediate needle thoracostomy (14-16G needle in the 2nd intercostal space, midclavicular line), later, install chest tube.
Explain the abbreviation O/E.
On examination
Explain the abbreviation B/G.
Background
Explain the abbreviation NSCLC.
Non-small-cell lung cancer
Describe the movement of the sternum during external respiration.
Pendulum-like
Where are the layers of the pleura (parietal and visceral) continuous with one another?
Around the hilum of the lung
What does the ligamentum arteriosum connect?
The arch of the aorta and the pulmonary trunk. It is the remnant of the ductus arteriosus which connected the pulmonary trunk and the aorta in intra-uterine life.
Which 2 major veins contribute to the superior vena cava?
The subclavian and internal jugular veins of the right and left side, join behind the medial end of the clavicle. This then forms the right and left brachiocephalic veins, contributing to the superior vena cava.
Which of the brachiocephalic veins is longer and more oblique?
Left
What vein minorly contributes to the superior vena cava, and in what way?
The azygos vein merges with the superior vena cava posteriorly before the SVC pierces the pericardial sac.
What are the only branches of the ascending aorta and where do they arise?
The only branches of the ascending aorta are the coronary arteries which arise at its start.
What are the 3 major arteries that arise of the arch of the aorta?
The brachiocephalic trunk (innominate artery), the left common carotid artery and the left subclavian artery
What does the brachiocephalic trunk divide into?
The innominate artery divides into the right subclavian and the right common carotid arteries.
What does the azygos vein arch over before merging with the superior vena cava?
The right main bronchus
On which side of the mediastinum are the 2 hemi-azygos veins localised?
Left. Only 1 on the right
List the branches of the trachea in order.
Trachea, primary main bronchi, secondary lobar bronchi (2/3), tertiary segmental bronchi (8/10), bronchioles, terminal bronchioles.
Name the lobes of the right and left lungs.
Right: superior, middle and inferior lobes
Left: superior and inferior lobes
What structure only occupies the mediastinum in childhood?
The thymus gland
How does blood enter the right atrium other than the 2 venae cavea?
By way of the coronary sinus (anterior to the venae cavae)
What is the wall between the left and right atria called?
The intra-atrial septum (lying obliquely)
What is the fossa ovale?
The fossa ovale is a thin oval patch on the inner intra-atrial septum. It is a remnant of the foramen ovale that connected the 2 atria in intrauterine life.
How many pulmonary veins enter the left atrium?
4, 2 from the right lung and 2 from the left
What is the left atrioventricular valve called?
The bicuspid, mitral valve
What is the right atrioventricular valve called?
The tricuspid valve
Name the 3 valves of the tricuspid valve.
Septal, anterior, posterior cusps
Where do the chordae tendineae arise?
The chordae tendineae arises from papillary muscle.
State the function of the chordae tendinaea.
To prevent the cusps of the valve from prolapsing into the atrium during systole.
What muscles forms a lining of criss-crossed pattern on the wall of the right ventricle?
Trabeculae carnae
What is the tapering part of the right ventricle that leads up to the pulmonary valve called?
It is called the infundibulum or the conus arteriosus. Uniquely, its lining is smooth.
Compare the shapes of the left and right ventricles in cross section.
The left ventricle’s walls are thicker and it has circular shape. The right ventricle is in a C-shape. Hence, the interventricular septum is curved.
How does the right coronary artery arise and terminate?
It arises from the right aortic sinus. It terminates at the right interventricular artery.
State the 3 arteries that supply each intercostal space.
The posterior intercostal artery, its collateral branch, anterior intercostal arteries.
From where are the posterior intercostal arteries derived?
The descending aorta (T3-12) or supreme intercostal artery (T1,2)
From where are the anterior intercostal arteries derived?
Internal thoracic (T1-6) and musculophrenic (T7-9) artery, which is derived from the subclavian artery.
Where do the anterior intercostal veins drain?
The musculophrenic and internal thoracic veins
Where does the posterior intercostal vein of T1 drain?
Direct to the brachiocephalic trunk
Where do the posterior intercostal veins of T2,3 drain?
T2,3’s veins unite to form the superior intercostal vein and enter the brachiocephalic trunk.
List the neurovascular structures of each intercostal space from superior to inferior.
Vein, artery, nerve
How are intercostal spaces innervated?
Intercostal nerves are numbered T1-11 corresponding to T vertebrae. The subcostal nerve, T12, runs below the 12th rib. Each nerve gives rise to a collateral nerve near the angle of the rib, which runs along the superior surface of the rib below. They originate from the anterior rami of the corresponding spinal nerves.
What are acini?
Saclike cavities in the gland, they are surrounded by secretory cells that produce milk.
On which quadrant of the breast is breast cancer most likely?
Superolateral quadrant - 60%
What are the atria and ventricles divided by superficially?
The coronary sulcus
What are the pectinate muscles?
The pectinate muscles arise from the crista terminalis and line the atria (mostly right).
Where does blood from the right atrium go to the right ventricle?
The right AV orifice/tricuspid orifice
What are the smooth and rough parts of the right atrium divided by?
The sulcus terminalis
Label the Y-shape formed by the semilunar valves.
The stems are called lunules. Their confluence is called a nodule.
Observe this diagram illustrating the attachments of the papillary muscles and cusps in the right ventricle.
Why is there a sinus at the semilunar valves of the pulmonary trunk and the aorta?
This sinus collects blood between the arterial wall and the cusps, to prevent the cusps from sticking to the wall and to help in closing the cusps. In the aorta, this is where the coronary arteries arise. The backflow of blood from the aorta fills these arteries.
The pericardiophrenic ligament is a continuous structure formed from the fibrous pericardium and what other structure?
The central tendon of the diaphragm
Compression of the heart due to pericardial effusion is termed what?
Cardiac tamponade
The thickest area of myocardium is found in which structure?
The left ventricle (fucking obviously)
Parasympathetic innervation of the heart is provided by which nerve?
The vagus nerve
In an intercostal space, where can the neurovascular bundle be found?
It is located in the costal groove on the inferior border of the upper rib. It is located between the internal intercostal and innermost intercostal muscles.
State the innervation of the diaphragmatic pleura.
Central part: phrenic nerve (C3,4,5)
Peripheral part: lower intercostal nerves (T7-12)
Where do pulmonary lymphatic nodes drain?
They drain to the bronchopulmonary (hilar) nodes.
At what level does the hilum of the lung lie?
4th to 5th costal cartilages
How does the phrenic nerve run relative to the hilum of the lung?
Anteriorly
Label this diagram of the thoracic cavity to the right of the mediastinum.
1=azygos vein
2=branch of right pulmonary artery to superior lobe
3=branches of sympathetic trunk to greater splanchnic nerve
4=diaphragm
5=inferior vena cava
6=shaft of 1st rib
7=oesophagus
8=pericardium over right atrium
9=costal pleura
10=right inferior pulmonary vein
11=right splanchnic nerve
12=right primary bronchus
13=right pulmonary artery
14=right subclavian artery
15=right superior pulmonary vein
16=right vagus nerve
17=6th, right, posterior, intercostal vessels under parietal pleura
18=right superior lobar bronchus
19=superior vena cava
20=sympathetic trunk and ganglion
State the arterial supply and venous drainage of the breast.
Arterial supply: internal thoracic artery, axillary arteries, posterior intercostal arteries
Venous drainage: axillary vein, internal thoracic vein
Where does lymph from the nipple, areola and lobules pass to?
Subareolar lymphatic plexus
Where does most of the lymph drain to in the breast? Where does the remaining lymph drain to?
In the breast at least 75% of lymph drains to the axillary lymph nodes.
Most of the remaining lymph drains to the parasternal lymph nodes or the opposite breast.
State the contents of the right and left carotid sheaths.
The right and left carotid sheaths contain the right and left internal jugular veins, the right and left common carotid arteries and the right and left vagus nerves.
What vessels run either side of the sternum?
The right and left internal thoracic arteries
Label this diagram.
1=cervical pleura
2=bronchial tree
3=costal pleura
4=pleural cavity
5=visceral pleura
6=costophrenic angles
7=diaphragmatic pleura
8=mediastinal pleura
9=lingula
10=cardiac notch
11=costal surface of left lung covered with visceral pleura
12=costal pleura
13=cervical pleura
14=trachea
7,8 and 12 are parts of the parietal pleura
What connects the diaphragmatic pleura to the diaphragm muscle?
The phrenicopleural fascia
What is special about mediastinal pleura?
At the mediastinal part of the pleura, parietal pleura is continuous with visceral pleura.
What are the attachments and functions of the pulmonary (pleural) ligament?
Attachments: connects the hilum of the lung to the diaphragm, formed by inferior pleural cuff
Functions: stability, movement and lymphatic drainage
What is thoracocentesis?
Thoracocentesis (pleural tap) is a procedure that aspirates excess pleural fluid.
What is the diagnostic standard for pleural effusions?
At least 300mL of pleural fluid in the pleural recesses
What are some causes of pneumothorax?
Spontaneous rupture bulla (resulting from COPD) or open external trauma.
State the nerve supply of the mediastinal pleura.
Phrenic nerve (C3,4,5)
State the nerve supply of the costal pleura.
Intercostal nerves (T1-11)
State the nerve supply of the diaphragmatic pleura.
Phrenic nerve(C3,4,5) and intercostal nerves (T6-11)
State the nerve supply of the visceral pleura.
Vagus nerve and sympathetic trunk
State the arterial supply of the parietal pleura.
Intercostal, internal thoracic and musculophrenic arteries
State the arterial supply of the visceral pleura.
Bronchial artery
What nodes are involved in the lymphatic drainage of the pleura?
Parietal pleura: intercostal, mediastinal and diaphragmatic lymph nodes
Visceral pleura: bronchopulmonary nodes
State the position of the phrenic nerve relative to the vagus nerve.
The phrenic nerve is lateral and anterior to the vagus nerve.
Name the fissures of the lungs.
In the right lung there is a horizontal fissure between the superior and middle lobes and an oblique fissure between the middle and inferior lobes. In the left lung, there is an oblique fissure between the superior and inferior lobes.
Label this diagram of the right lung.
1=subclavian artery
2=subclavian vein
3=right brachiocephalic vein
4=left brachiocephalic vein
5=superior vena cava (out of which emerges the arch of the azygos vein)
6=pulmonary artery
7=pulmonary veins (inferior to which lies the pulmonary ligament)
8=inferior vena cava
9=diaphragm
10=azygos vein
11=oesophagus
12=bronchus
13=bronchus to superior lobe
14=rib 1
Label this diagram of the left lung.
1=rib 1
2=bronchus
3=eosphagus
4=thoracic aorta
5=diaphragm
6=heart
7=pulmonary veins, inferior to which runs the pleural ligament
8=pulmonary artery
9=aortic arch
10=left brachiocephalic vein
11=left subclavian artery
What supplies blood to the bronchi, lung tissue and visceral pleura?
Bronchial arteries, contributing to 1% of total pulmonary blood supply.
Where do bronchial veins drain into?
Bronchial veins drain into the hemiazygos and azygos veins.
What is the source of nervous supply to the lungs?
Sympathetic and parasympathetic fibers from the pulmonary plexus
State the lymphatic plexuses of the lungs.
Superficial and deep lymphatic plexus
Describe the difference between the right and left main bronchus.
The right main bronchus is wider, shorter and courses more vertically.
What is pneumonia? State its symptoms, causes and treatment.
Pneumonia is inflammation of the lungs affecting alveoli. Symptoms include: dry cough, chest pain, fever, fatigue, tachycardia. It is caused by viruses or bacteria. Treatment involves antibiotics.
Define bronchoscopy.
Bronchoscopy allows visualization of the airways using a bronchoscope inserted through the mouth or nose.
Define segmental atelectasis.
Segmental atelectasis is the partial collapse of a lung segment due to airway obstruction, impaired surfactant function or compression.
Localize the apex and base of the lungs.
The apex lies above the clavicle. The base lies on the diaphragm.
State the position of the lungs relevant to the bronchus.
RALS
Right lung: PA is anterior to the bronchus
Left lung: PA is superior to the bronchus
Where is a foreign body most likely to pass in the airways system?
A foreign body is more likely to pass through the right main bronchus and into the right lung.
From what germ layer does the cardiovascular system arise?
The mesoderm
Which organ system is the first to function in a foetus?
The cardiovascular system
When will the foetal heart first cause circulation?
3 weeks
Where is the cardiogenic area?
The cardiogenic area is where the heart first begins to develop. It is derived from splanchnic mesoderm cells. Elongated cardiogenic cords form here.
State the progression of mesenchyme in the heart.
Mesenchyme thickens to form the myoepicardial mantle. Which then becomes the epicardium and myocardium.
What is the heart tube made of?
Myoepicardial layer, cardiac jelly (secreted by myoblasts, is connective tissue), endocardium
State the 5 primitive heart regions.
Truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and the sinus venosus
Which cardiac structure receives the umbilical vein, the vitelline vein and the common cardinal veins?
The sinus venosus
What does the truncus arteriosus mature into?
Ascending aorta and pulmonary trunk
What does the bulbus cordis mature into?
Right ventricle
What does the primitive ventricle mature into?
Left ventricle
What does the primitive atrium mature into?
The anterior atria and the auricles
What does the sinus venosus mature into?
Posterior right atrium, SA node and coronary sinus
What is the precursor structure to the AV septum?
Endocardial cushions
Name the septa of the immature IA septum.
Septum primum and septum secondum
What causes the formation of the foramen secondum?
Apoptosis of the septum primum upon minimising the foramen (ovale) primum
State the time period in which the IV septum develops.
Between the 4th and 7th week
State the development of the heart in days.
18: heart appears from cardiogenic area
20: cardiogenic cords-endocardial tubes-heart tube
21: pumping blood
22: heart tube develops into 5 primitive structures
22-28: heart is in an S-shape
28: septa form
W5-8: AV valves form
W5-9: semilunar valves form
What organ is formed during gastrulation?
The gut
When does upper respiratory tract formation begin?
Weeks 3-4
Describe upper respiratory tract formation.
The olfactory placode is a thickened region of the ectoderm and it develops in the anteroinferior part of the head. Placode invaginates posteriorly to connect with the foregut. Foregut develops from endoderm and becomes pharynx. A thin oronasal membrane separates the 2 cavities. The primary palate forms at 5 weeks from 2 medial swellings of the maxillary processes that merge to form the palate. At 7 weeks the oronasal membrane ruptures and forms the oronasal cavity.
Fill out a table discussing the products of the gut tube, from the foregut, midgut and hind gut as well as its derivatives.
Where is the superior mediastinum?
Above the sternal angle.
How are the boundaries of the inferior mediastinum dictated?
They are dictated by the position of the heart and pericardium as anterior, middle and posterior to it.
Where is the thymus located?
The superior and anteroinferior mediastinum
State the major structures of the superior mediastinum from anterior to posterior.
Thymus, brachiocephalic veins, arteries, trachea, oesophagus, thoracic duct
Label this diagram of the inferior view of a cross-section of the mediastinum, viewed at the level of the middle of the manubrium (~T2)
1=manubrium
2=thymus
3=right brachiocephalic vein
4=right phrenic nerve
5=right vagus nerve
6=trachea
7=oesophagus
8=sympathetic trunk
9=thoracic duct
10=left recurrent laryngeal nerve
11=left subclavian artery
12=left vagus nerve
13=left common carotid artery
14=left phrenic nerve
15=brachiocephalic trunk
16=left brachiocephalic vein
17=sternoclavicular joint
Label this diagram of the inferior view of a cross-section of the mediastinum, viewed at the level of the superior portion of the body of the sternum (~T4).
1=body of sternum
2=lymph node
3=SVC
4=right phrenic nerve
5=trachea
6=right vagus nerve
7=oesophagus
8=thoracic duct
9=left recurrent laryngeal nerve
10=arch of aorta
11=left vagus nerve
12=left phrenic nerve
13=thymus
State the contents of the anterior mediastinum.
Thymus, internal thoracic vessels, lymph nodes, fat
State the contents of the middle mediastinum.
Heart, ascending aorta, pulmonary trunk, superior/inferior vena cava, pulmonary veins, right/left phrenic nerves, cardiac plexus lymph nodes
State the contents of the posterior mediatinum.
Oesophagus, descending aorta, azygos veins, thoracic duct/lymph nodes, sympathetic trunk, thoracic splanchnic nerves
What is the name of the complete ring off cartilage around the oesophagus?
Cricoid cartilage, level with C6
What vein forms a direct connection between the SVC and the IVC?
The azygos vein
Where do the ascending lumbar veins drain?
The right ascending lumbar vein drains to the azygos vein. The left ascending lumbar vein drains to the hemiazygos vein.
Why is the azygos vein advantageous when other major veins are blocked?
The azygos vein is a collateral venous pathway, becoming a vital shunt if major pathways of venous return are obstructed.
Where does blood from posterior intercostal veins drain?
The azygos vein
What is the left venous angle?
The left venous angle is the junction where the left subclavian vein and left internal jugular vein meet to form the left brachiocephalic vein.
What are common sites of oesophageal constriction?
