CVR: Anatomy of the Thorax Flashcards
What is the base of the heart?
Superior surface of the heart (formed mainly of the left atrium).
Where is the sternal angle, and at what vertebral level?
Between the manubrium and the sternal body, at level between 4th & 5th thoracic vertebra.
How does the sternal angle divide the mediastinum?
Above sternal angle = superior mediastinum.
Below sternal angle = inferior mediastinum.
What are the three sets of intercostal muscles?
Which are for inspiration/expiration?
External = for inspiration.
Internal & innermost = for expiration.
Which lung has more lobes, the left or right?
The right; 3 lobes. Left only has 2 lobes.
What is the fossa ovalis?
Depressed structure in between right and left atriums, remnant of foramen ovale.
What are the smooth and rough portions of the atria called?
Smooth = sinus venarum
Rough = trabeculated
What is the crista terminalis?
Vertical ridge of myocardium in the right atrium, separates sinus venarum and trabeculated portions of atrium.
Does the left atrium have a crista terminalis?
No, only the right atrium has a crista terminalis.
In the fibrous skeleton of the heart, which valves are connected, and what is this connection called?
Mitral and aortic valves.
The aorto-mitral continuity.
Where does the coronary sinus drain into?
The right atrium.
Where do the coronary arteries lie in the heart?
Under the pericardium, embedded in fat in grooves in between the chambers of the heart.
What arteries does the left mainstem split into?
Left anterior descending (which splits into septal and diagonal arteries)
Circumflex (which becomes obtuse marginal artery)
In coronary arterial dominance, 80-85% of people are right dominant. What does this mean?
The posterior descending artery (PDA) is supplied by the right coronary artery as opposed to circumflex in left-dominance (or both in co-dominance!).
What divides the anterior, middle, and posterior mediastinum?
The pericardium.
How are the atrioventricular valves prevented from everting into the atria during systole?
Papillary muscles (part of the ventricle) are attached to the valves via chordae tendinae.
Which coronary artery runs in the anterior inter-ventricular groove?
Left Anterior Descending.
What part of the heart does the diagonal coronary artery branch supply?
Left ventricle.
Which groove does the circumflex artery run in?
Left atrioventricular groove.
What part of the heart does the obtuse marginal branches supply?
Posterolateral left ventricular wall
Which groove does the right coronary artery run in?
The right atrioventricular groove.
Which groove does the posterior descending artery run in and where does it supply?
Posterior interventrciular groove.
Supplies inferior septum and left ventricle.
The mitral valve is between the left atrium and left ventricle. How many leaflets/cusps does it have?
Two cusps/leaflets.
What is the mediastinum?
The thoracic cavity excluding the lungs (but includes the trachea).
The right coronary artery and the left main stem branch from what major blood vessel?
Ascending aorta/aortic root.
What blood vessels does the brachiocephalic trunk of the aortic arch bifurcate into?
Right common carotid.
Right subclavian
One branch of the aortic arch is the brachiocephalic trunk. Name the other two branches.
Left common carotid.
Left subclavian.
Where does the descending aorta lead to?
The thoracic and then abdominal aorta, supplying blood to lower body.
What fibrous cord-like remanent of the ductus arteriosus connects the pulmonary trunk to the aortic arch?
Ligamentum arteriosum.
What veins converge to form the superior vena cava?
Left and right brachiocephalic veins.
Is the oesophagus anterior or posterior to the trachea?
Posterior.
The phrenic nerve innervates the diaphragm and what other structure?
The pericardium.
What are the ear-like appendages/outpouchings of the walls of the atria called?
Auricles.
In cardiac tamponade, the heart is compressed and unable to fill properly. Which layer of the pericardium is responsible for this and why?
Parietal layer of the pericardium - fibrous and cannot stretch.
What does the recurrent laryngeal nerve originate from?
Vagus nerve - recurrent laryngeal nerve ascends back up the neck to the larynx.
Why might lung cancer cause a hoarse voice?
Cancer at apex of lung may involve the recurrent laryngeal nerves, leading to paralysis of the ipsilateral intrinsic laryngeal muscles, so cannot fully adduct vocal cords.
From what spinal nerves do the phrenic nerves originate from?
C3, C4, C5 (“keep the diaphragm alive”).
What are the three parts of the sternum?
Manubrium, sternal body, xiphoid process/xiphisternum.
What is the name of the joint where the manubrium articulates with the clavicle?
The sternoclavicular joint.
What is another term for the sternal angle, other than the angle of Louis?
Manubriosternal joint.
What does the manubrium articulate with?
Clavicles, first ribs, and the sternal body.
Where is the suprasternal (jugular) notch?
Superior border of the sternum.
With which ribs does the body of the sternum articulate, and what are these joints called?
Ribs 2-7 (the “true” ribs).
Sternocostal joints.
How many pairs of ribs are there and which vertebra do they attach to?
12 pairs, each pair attaching to a thoracic vertebra (of which there are 12!).
What is the costal margin?
The lowest part of the ribs anteriorly.
What is the term for where the ribs articulate with their costal cartilage?
Costochondral joints.
How are ribs 8-10 related?
Their costal cartilage unite and join the 7th costal cartilage
Why are ribs 11 & 12 different to the other ribs?
They are shorter, don’t have costal cartilage and don’t articulate with the sternum, they are “floating” ribs.
Describe how ribs articulate with vertebra at the costovertebral joints.
Tubercle of rib articulates with transverse process, head of rib articulates with vertebral body above and below.
What is the costal groove and what is its function?
Groove in the internal aspect of rib, protects the neurovascular bundle.
What forms the boundary of the superior thoracic aperture?
Manubrium, first ribs, and first thoracic vertebra.
What is a dermatome?
An area of skin innervated by a single spinal nerve.
Are the dermatomes of the thoracic wall in vertical strips or horizontal strips, and which spinal nerves innervate them?
Horizontal strips.
T1-T12
(same as the ribs! just all the thoracic vertebra).
In which dermatome is the umbillicus?
T10
In which dermatome are the nipples?
T4
Where is the axillary tail and what tissue is it part of?
The part of the breast tissue extending towards the anterior axilla.
In breast tissue, what is a lobule composed, and what does it lead to?
Glandular or secretory tissue.
Leading to ducts which converge on the nipple.
Which two arteries supply the breast?
Axillary artery, and anterior intercostal arteries, which are branches of the subclavian artery.
What veins return blood from the breast?
Axillary and internal thoracic veins.
What nerves supply somatic nerves and sympathetic fibres to the breast?
Intercostal nerves.
Why are the axillary lymph nodes often involved in the spread of breast cancer?
Because they drain most of the lymph from the breast.
What are the five axillary lymph node groups?
“CHAPS”
- Central
- Humeral
- Apical
- Pectoral
- Subscapular
Where do the axillary lymph nodes drain lymph from (5 places)?
“U SCAB”
- Upper limb
- Scapular region
- Chest wall
- Abdominal wall
- Breast
What is the most superficial muscle of the anterior thoracic wall?
Pectoralis major
Where is the pectoralis minor muscle?
Deep to pectoralis major (underneath it) in the anterior thoracic wall.
Which superficial muscle sweeps around the lateral aspect of the thoracic cage and attaches to the scapula and ribs 1-8?
The serratus anterior muscle.
What structures would you find in the intercostal space?
Intercostal muscles (3 layers; external, internal, innermost).
Neurovascular bundle (artery, vein, nerve).
Which artery do the posterior intercostal arteries branch from, and which vein do they drain to?
Descending aorta.
Azygos.
Which artery do the anterior intercostal arteries branch from, and which vein do they drain to?
Internal thoracic artery (which branches from the subclavian artery).
Internal thoracic vein.
What produces pleural fluid?
The pleural cells.
What are the two potential spaces the lungs expand into during deep inspiration?
Costodiaphragmatic recess and the costomediastinal recess (“gutters” where different areas of the parietal pleura meet).
Is the visceral pleural innervated by somatic or autonomic sensory nerves?
Autonomic only.
Is the apex of the lungs the most superior aspect or most inferior?
Superior aspect of the lungs is the apex.
What is the lingula in the lungs?
Anterior extension of the superior lobe in the left lung which extends over the heart.
How many lobes does the right lung have and how are they divided (by which fissures)?
Right lung has 3 lobes.
Superior and middle lobe separated by oblique fissure.
Middle and inferior lobe separated by horizontal fissure.
Which ribs mark the inferior border of the lungs (anteriorly, laterally, and posteriorly)? How is this different to the parietal pleura?
Anteriorly = 6th rib midclavicular
Laterally = 8th rib midaxillary
Posteriorly = 10th rib lateral to vertebral column.
Parietal pleura extends 2 ribs lower in each place.
What is the hilum of the lung?
Region on mediastinal surface where pulmonary artery, veins, and main bronchus enter and exit the lung.
A foreign body entering the trachea is more likely to end up in the right or left main bronchus and why?
Right main bronchus.
Because the right main bronchus is shorter, wider, descends more vertically than left main bronchus.
In the bronchial tree, which bronchi branch from the main bronchus to supply each lobe?
Lobar bronchi.
In the bronchial tree, which bronchi supply each bronchopulmonary segment?
Segmental bronchi (branch from lobar bronchi).
How many bronchopulmonary segments are there in each lung?
Right lung = 10
Left lung = 8-9
What arteries supply lung tissue and what main artery do they originate from?
Bronchial arteries originating from the descending aorta.
Parasympathetic or sympathetic fibres stimulate relaxation of bronchial smooth muscle (bronchodilation)?
Sympathetic.
What bones/cartilage does the diaphragm attach to?
Xiphoid process, costal margin, and lumbar vertebra.
Is the diaphragm made of smooth or skeletal muscle?
Skeletal.
Does expiration always involve contraction of internal intercostal muscles?
No, at rest/normal quiet breathing, expiration is passive. Relaxation of diaphragm and recoil of lung tissue is enough.
In vigorous breathing, active expiration uses internal intercostal muscles.
What is mesothelioma?
Malignancy of the pleura.
What do the following arterial vessels have in common?Posterior intercostal arteries, bronchial arteries, oesophageal, pericardial, and phrenic branches.
They all originate from the descending thoracic aorta.
What is the mnemonic for the diaphragmatic apertures of major structures?
“I 8 10 EGGS AT 12”
IVC = T8
oEsophaGus & vaGus = T10
Aorta & Thoracic duct = T12
Where do the azygos veins drain from, and what vessel do they drain into?
The azygos veins drains blood from the posterior thoracic wall (posterior intercostal veins, oesophageal, and bronchial veins) and returns the blood into the superior vena cava.
Where is the azygos vein?
In the posterior mediastinum, on the right side of the vertebral column.
What does the thoracic duct lie between?
Between the oesophagus and the aorta.
What does lymph from the lower limbs, pelvis, and abdomen flow into in the abdomen before entering the thoracic duct?
Cisterna chyli
What structure in the lymph system returns most of the body’s lymph to the venous system?
The thoracic duct.
Where does the thoracic duct terminate and return lymph to the venous system?
At the junction between the left internal jugular vein and the left subclavian vein.
How does lymph drain from the right side of the head and neck, and the right upper limb into the venous system?
Lymph drains into lymphatic ducts which enter the venous system at the junction of the right internal jugular and right subclavian veins.
Where are the sympathetic trunks?
Either side of the vertebral columns.
Where do sympathetic fibres leave the spinal cord to join the sympathetic trunks?
T1-L3 vertebral segments.
What are splanchnic nerves?
Autonomic nerves that exit spinal cord at different vertebral levels, pass through the sympathetic trunk to then combine and travel together to ganglia closer to their target effector.
What are the three abdominopelvic splanchnic nerves and what vertebra do they originate from?
Greater splanchnic nerve, T5-T9
Lesser splanchnic nerve, T10-T11
Least splanchnic nerve, T12
What conveys sympathetic fibres to the thoracic viscera and other organs of the thorax?
The cardiopulmonary splanchnic nerves.
What conveys parasympathetic fibres to the thoracic viscera?
The vagus nerves.
What does the cardiac plexus innervate?
The sinoatrial node to increase (sympathetic) or decrease (parasympathetic) HR and contractility.
What innervates the bronchi?
The pulmonary plexus.
What does the oesophageal plexus do?
Innervate the oesophagus to inhibit (sympathetic) or stimulate (parasympathetic) peristalsis.
What is the difference in perception of pain from visceral afferents as opposed to somatic afferents?
Visceral afferent fibres convey less detailed information about the pain, so pain might feel dull/aching/burning/tightness, hard to describe and locate.
Why does a painful stimulus affecting the diaphragm cause perception of pain in the neck/shoulder?
Painful stimulus from the phrenic nerve enters the spinal cord at C3-C5 and the brain interprets this as pain coming from the C3-C5 dermatomes; the side of the neck and shoulder.
Why do people suffering an MI often have pain in their left arm?
The cardiopulmonary splanchnic nerves come from C4-T5, so the brain interprets this as pain coming from the C4-T5 dermatomes; part of the neck, thorax, and left arm.
The right posterior intercostal veins drain directly into the azygos vein. How does this differ to how the left posterior intercostal veins drain into the azygos vein?
The left posterior intercostal veins first drain into the accessory hemiazygos and the hemiazygos veins on the left side of the vertebral column, which then empty into the azygos.
Between which two muscle layers is the intercostal neurovascular bundle located?
Internal and innermost intercostal muscles
The internal thoracic artery branches from which larger artery?
The internal thoracic artery branches from the subclavian artery.
The right recurrent laryngeal nerve loops under which structure, before ascending back into the neck?
Right subclavian artery.
The left recurrent laryngeal nerve loops under which structure, before ascending back into the neck?
Descends into the thorax and loops under the arch of the aorta.
The diagonal artery (or arteries) typically arise from which larger coronary artery?
Left anterior descending
Which arteries branch directly from the descending (thoracic) aorta?
Posterior intercostal arteries
The anterior intercostal arteries branch from which arteries to supply the anterior thoracic wall?
The internal thoracic arteries.
The internal thoracic arteries branch from which arteries to supply the anterior part of the thoracic wall?
The subclavian arteries.
Which nerve runs posterior to the hila of the lung, the phrenic or vagus nerve?
Vagus nerve.
The phrenic nerve is anterior to the hila.
At what vertebral level is the carina?
T5, same level as the sternal angle.
Describe the tracheal cartilage.
Semi-complete, does not join posteriorly where the oesophagus lies, so that neck can bend.
What is the difference between the respiratory bronchioles and the terminal bronchioles?
The respiratory bronchioles are the first part of the airway where gas exchange can occur, they have discernible alveoli protruding from them.
Terminal bronchioles are the last conducting airways, they do not have the ability for gas exchange.
There are approximately 30,000 acini per lung. What is an acinus?
The lung portion distal to a terminal bronchiole.
What is the diaphragm?
A dome-shaped fibromuscular sheet, separating the thorax from the abdomen.
Branches of the bronchial arteries supply bronchial and peri-bronchial tissue, and the visceral pleura. What major vessel do the bronchial arteries originate from?
The descending aorta.
