CVR Anatomy Flashcards
How is the thoracic cavity continuous with the neck?
Via the superior thoracic aperture.
How is the thoracic cavity separated from the abdominal cavity?
By the diaphragm - a sheet of skeletal muscle vital for breathing.
What does the thorax contain?
- Heart.
- Lungs.
- Trachea.
- Oesophagus.
- Arteries and veins.
- Nerves.
- Lymphatic vessels.
What is the thoracic cage composed of? What is its purpose?
- The sternum, 12 pairs of ribs, and thoracic
vertebrae. - Semi-rigid and moves with breathing to
allow the lungs to expand. - Protects the thoracic and some abdominal
viscera. - Provides an attachment for the muscles of
breathing and muscles that move the upper
limbs.
Where does the sternum lie? What 3 parts is it composed of?
- Anteriorly in the midline of the thoracic
cage. - Made up of: manubrium, body, and xiphoid
process (superior -> inferior).
What is the notch on the superior border of the manubrium called?
Suprastenral (jugular) notch.
Where does the manubrium articulate with the clavicle laterally?
The sternoclavicular joint.
Where does the manubrium articulate with the body of the sternum?
The manubriosternal joint, AKA the sternal angle, or the ‘angle of Louis’.
What are the anterior parts of the ribs composed of? Why?
Costal cartilage, to give the thoracic cage some ‘springiness’.
Where do the ribs articulate with their costal cartilages?
Costochondrial joints.
Where do the costal cartilages of the upper ribs articulate with the sternum?
Sternocostal joints.
What do the ribs articulate with posteriorly? Where?
Thoracic vertebrae, at costovertebral joints.
What lies in the intercostal spaces? What do they do?
- Intercostal muscles.
- Move the thorax for breathing.
Where do the thoracic vertebrae lie? Where do they articulate with each other?
- Posteriorly in the midline of the thoracic cage.
- Intervertebral joints.
What are the four chambers of the heart? Which are the pumping chambers? What differences do they have?
- The right and left atria, and the right and left
ventricles. - The ventricles are the pumping chambers,
so they have thicker muscular walls than the atria.
Where are atrioventricular valves found? What are they called?
- Between the atria and ventricles.
- The tricuspid valve on the right.
- The mitral valve on the left.
Where are semilunar valves found? What are they called?
- Between the ventricles and the large blood
vessels that carry blood from them. - Pulmonary valve at the entrance to the
pulmonary trunk. - Aortic valve at the entrance to the aorta.
What supplies the myocardium with blood?
The coronary arteries.
How does the heart work as a muscular pump?
Specialised nerve cells and fibres generate and conduct electrical energy that stimulates contraction of the myocardium spontaneously, these cells are under autonomic control.
What is the cardiopulmonary circulation?
- The circulation between the heart and the
lungs. - Arteries carry deoxygenated blood and
veins carry oxygenated blood. - Opposite for the systemic circulation of the
rest of the body. - Veins carry blood to heart.
- Arteries carry blood away from heart.
- True for cardiopulmonary and systemic.
What does parasympathetic stimulation do to heart rate?
Decreases.
What does sympathetic stimulation do to heart rate?
Increases heart rate.
What are the steps of cardiopulmonary circulation?
- Right atrium gets deoxygenated blood from
superior and inferior vena cava (veins). - Blood flows from right atrium -> right
ventricle. - Right ventricle pumps deoxygenated blood
to lungs via pulmonary arteries. - Gas exchange at lungs.
- Oxygenated blood returns from lungs via
pulmonary veins to the left atrium. - Blood flows from left atrium -> left ventricle.
- Left ventricle pumps oxygenated blood via
aorta to the rest of the body.
What are alveoli? Approximately how many alveoli does an adult lung contain?
- Microscopic air sacs.
- Around 300 million per lung.
How are the lungs divided into lobes? What separates the lobes?
- Right lung has 3 lobes: superior, middle,
inferior. - Left lung has 2 lobes: superior and inferior.
- Fissures separate the lobes.
What is each lung served by? What are their functions?
- One pulmonary artery (deoxygenated blood
into the lung). - Two pulmonary veins (oxygenated blood
from the lung). - One main bronchus (air between lung and
trachea).
What are the membranes that cover the lungs called?
Visceral and parietal pleura.
What is the bronchial tree?
- The branching system of tubes that conduct
air into and out of the lungs. - Trachea bifurcates -> left and right main
bronchi -> left and right lungs respectively. - Main bronchi divides -> smaller bronchi,
divides -> bronchioles. - Bronchioles divide smaller and smaller,
smallest conduct air to/from alveoli.
What do the walls of the bronchi and trachea contain?
Smooth muscle and cartilage.
Cartilage acts as a scaffold to ensure they remain open.
What do the walls of bronchioles contain?
Smooth muscle only, which can contract and relax.
What does parasympathetic stimulation do to bronchioles?
Narrows = bronchoconstriction.
What does sympathetic stimulation do to bronchioles?
Opens = bronchodilation.
What are the three skills of surface anatomy?
Looking, feeling (palpating), and listening (auscultating).
What is a key surface landmark of the thorax?
The sternal angle, as it lies at the same level as the second ribs, allowing us to count the rest.
What is the skin of the thoracic wall innervated by?
Spinal nerves T1 -> T12.
What are the skeletal muscles of the thoracic wall innervated by?
Somatic motor fibres in spinal nerves T1 -> T12.
What innervates sweat glands and the smooth muscle of blood vessels and hair follicles?
Sympathetic fibres.
What does the breast contain?
- Fat.
- Glandular/secretory tissue arranged in
lobules. - Ducts which converge on the nipple.
- Connective tissue and ligaments.
- Blood vessels and lymphatics.
What blood vessels is the breast primarily supplied by?
Anterior intercostal arteries (branches from the internal thoracic artery - arises from subclavian artery), and the axillary artery.
What supplies somatic nerves and sympathetic fibres to the breast? What do these fibres innervate?
Intercostal nerves.
Somatic sensory fibres -> skin of the breast.
Sympathetic fibres -> smooth muscle in the blood vessel walls and nipple.
What are the 5 groups of lymph nodes in the axilla? What do they drain? What is unique about one of these groups?
- Central, pectoral, humeral, subscapular, and apical.
- Drain the breast, upper limb, chest wall, scapular region, and the abdominal wall.
- The apical nodes receive lymph from all other lymph nodes in the axilla, because they drain the most, they are often involved in the spread of breast cancer.
Which ribs are typical/atypical?
Ribs 3 -> 9 = typical.
Ribs 1 -> 2, and 10 -> 12 = atypical.
What forms the boundary of the superior thoracic aperture? What is this?
- The manubrium, the first ribs, and the first thoracic vertebrae.
- The passageway through which structures pass between the neck and the thorax.
What are the 3 types of intercostal muscles? What do they do?
- External, internal, and innermost.
- Move the ribs and alter dimensions of the thoracic cavity with inspiration and expiration.
Where would you find the pectoralis major?
Most superficial muscle of the anterior chest wall.
Attached to the upper humerus, the clavicle, and the upper six ribs.
Where would you find the pectoralis minor?
Deep to the pectoralis major.
Attached to the scapula, and ribs 3 -> 5.
Where would you find the serratus anterior?
Superficial muscle sweeping around the lateral aspect of the thoracic cage.
Attached to the scapula, and the upper eight ribs.
What are some clinical relevancies of the pectoral region, thoracic cage, and lungs?
- Rib fractures.
- Shingles.
- Breast cancer.
What do the intercostal spaces contain?
- Three layers of intercostal muscle and their associated membranes.
- A neurovascular bundle containing an intercostal nerve, artery, and vein.
Which direction are the fibres orientated in in the…
A.) external intercostal muscle
B.) internal intercostal muscle
C.) innermost intercostal muscle
A.) Antero-inferiorly.
B.) Postero-inferiorly.
C.) Postero-inferiorly.
How does the external intercostal muscle act on the ribs?
Contraction pulls the ribs superiorly, hence is most active in inspiration.
How does the internal intercostal muscle act on the ribs?
Contraction pulls the ribs inferiorly, hence is most active in expiration.
Where do the external and internal intercostal muscles become membraneous?
External - anterior of the intercostal space.
Internal - posterior of the intercostal space.
What lies between the innermost intercostal muscle and the parietal pleura?
The endothoracic fascia.
Where do you find the neurovascular bundle in each intercostal space?
In the plane between the internal and innermost intercostal muscle.
Inferior border of the rib, superior to the space.
In a shallow costal groove on the deep surface of the rib.
What are the posterior intercostal arteries branches from?
The descending aorta.
What do the anterior and posterior intercostal veins drain into?
Anterior - the internal thoracic vein.
Posterior - azygos system of veins.
Describe the intercostal nerves. What do they innervate?
Somatic, containing motor and sensory fibres. Also carry sympathetic fibres.
Innervate the skin of the chest wall, and the parietal pleura.
Describe the pleurae.
Parietal pleura - lines inside of the thorax, visible with the naked eye.
Visceral pleura - covers surface of the lungs and extends into the fissures, not visible with the naked eye.
Pleural cavity - thin space filled with pleural fluid, lying between the pleurae.
Describe where you would find the different parts of the parietal pleura.
Cervical pleura - covers the apex of the lung.
Costal pleura - adjacent to ribs.
Mediastinal pleura - adjacent to the heart.
Diaphragmatic pleura - adjacent to the diaphragm.
Which nerves innervate the two pleural layers? Effects on sensation?
Parietal pleura - intercostal nerves, somatic sensory fibres carry sensation to consciousness -> very painful.
Visceral pleura - autonomic sensory nerves, doesn’t usually reach conscious perception.
Describe the fissures in the lobes of the lungs.
Both lungs have oblique fissures.
- Left: separates the superior and inferior lobes.
- Right: separates the superior and middle lobes from the inferior lobe.
Right lung has a horizontal fissure.
- Separates the superior and middle lobes.
Describe the positioning of the surfaces of the lung.
Costal surface - adjacent to ribs.
Mediastinal surface - adjacent to heart.
Diaphragmatic surface - inferior surface of the lung.
Describe the borders of the lungs.
Anterior border - sharp and tapered.
Posterior border - thick and rounded.
Inferior border - sharp and tapered.
Where is the root of the lung found? What does it contain?
Between the heart and the lung.
The pulmonary artery, pulmonary veins, and main bronchus. Pleura encloses it.
Where is the hilum of the lung found? What does it contain? Discuss the position of these components.
Mediastinal surface of the lung.
Where the pulmonary artery, pulmonary veins, and main bronchus enter and exit the lung.
Hilum of right lung - pulmonary artery is anterior to the main bronchus.
Hilum of left lung - pulmonary artery is superior to the main bronchus.
Pulmonary veins most anterior and inferior in both.
Where does the trachea bifurcate? How is this marked internally?
The sternal angle.
Marked by a ridge of cartilage called the carina.
When a foreign body enters the trachea, which bronchi is it more likely to enter? Why?
The right main bronchus.
Shorter, wider, and descends more vertically.
Describe the branching system of the bronchial tree. Include quantities.
Main bronchus -> lobar bronchi (3 in the right, 2 in the left - 1 for each lobe).
Lobar bronchus -> segmental bronchi (~10 in each lung to serve the 10 bronchopulmonary segments).
Segmental bronchus -> bronchioles (get smaller with each division, smallest = alveoli for gas exchange).
What is the space between the inferior border of the lungs and the inferior extent of the parietal pleura called?
The costodiaphragmatic recess.
Describe the locations of the borders of the lung using surface anatomy.
Apex - projects into the lower neck, just superior to the medial end of the clavicle.
Inferior border lies at:
- 6th rib anteriorly (midclavicular line).
- 8th rib laterally (midaxillary line).
- 10th rib posteriorly (at the vertebral column).
Describe where the parietal pleura extends to using surface anatomy.
- 8th rib anteriorly (midclavicular line).
- 10th rib laterally (midaxillary line).
- 12th rib posteriorly (at the vertebral column).
Describe the location of the fissures of the lobes using surface anatomy.
Oblique fissure - 4th rib posteriorly, to 6th costal cartilage anteriorly.
Horizontal fissure - anteriorly from the 4th costal cartilage, intersects the oblique fissure.
Describe the diaphragm and its function.
Broad, thin, domed sheet of skeletal muscle separating the thoracic and abdominal cavities.
Central part is not muscular but fibrous - the central tendon.
Essential to the mechanics of breathing.
What is the diaphragm attached to? Which nerves innervate the diaphragm?
The xiphoid process, costal margin, and the lumbar vertebrae.
Right and left phrenic nerves innervate the right and left sides. These are somatic nerves formed in the neck by fibres from C3 -> C5 spinal nerves, hence contain motor and sensory fibres.
What happens to the diaphragm during inspiration?
Diaphragm contracts, muscle fibres of right and left sides pulled towards their peripheral attachment -> domes flatten = increased intrathoracic volume for lungs to expand.
What happens to the diaphragm during expiration?
Diaphragm relaxes and domes superiorly = decreased intrathoracic volume for lungs to expand, driving expiration of air from the lungs.
Which three planes do the dimensions of the thoracic cavity change in during ventilation?
Vertically: due to contraction/relaxation of diaphragm.
Laterally: due to contraction of the intercostal muscles moving the ribs.
Anterior-posteriorly (AP): due to movement of the sternum secondary to rib movement.
What is the importance of the pleural fluid?
Creates and maintains surface tension, keeping the lung and the thoracic wall ‘together’, preventing the lung from ‘collapsing’ away.
If the surface tension is broken, the ventilation may become dysfunctional.
Describe inspiration.
Diaphragm and external intercostal muscles contract -> increased intrathoracic volume. (Diaphragm flattened, ribs are pulled superiorly and laterally, and sternum pulled superiorly and anteriorly).
Lungs expand with the thoracic wall due to surface tension.
Pressure in lungs decreases below atmospheric pressure and air is drawn into the lungs.
Describe expiration.
Diaphragm and external intercostal muscles relax, internal intercostal muscles contract -> decreased intrathoracic volume.
(Diaphragm domes superiorly, internal intercostal muscles pull ribs inferiorly, ribs pull the sternum inferiorly and posteriorly).
Lungs recoil.
Pressure in lungs increases above atmospheric pressure and air is expelled from the lungs.
Which muscles are involved in different types of breathing?
Normal - diaphragm mainly.
Vigorous - intercostal muscles become important.
Very vigorous/forced - accessory muscles of breathing contribute.
What are some clinical relevancies of the thoracic cage, the pleura, and the lungs?
- Pleuritic chest pain.
- Pneumothorax and haemothorax.
- Pleural effusion.
- Lung cancer and mesothelioma.
- Pulmonary embolism.
- Dyspnoea.
- Paralysis of the diaphragm.
Where is the mediastinum?
- Lies between the lungs, extends from
superior thoracic aperture superiorly ->
diaphragm inferiorly, and the sternum
anteriorly -> thoracic vertebrae posteriorly.
What does the mediastinum contain?
- Heart and pericardium.
- Greater vessels that go in/out of heart.
- Veins that drain the chest wall.
- Trachea and main bronchi.
- Oesophagus.
- Nerves.
- Lymphatics.
- The thymus gland.
How is the mediastinum divided?
- Superior and inferior, line runs from sternal
angle -> T4/5 junction. - Inferior split into anterior, middle, and
posterior.
What can be found in/where are the different sections of the inferior mediastinum?
Anterior -> sternum to pericardial sac, thymus gland in children, remnant in adults.
Middle -> heart inside pericardial sac, pulmonary trunk, and ascending aorta.
Posterior -> pericardial sac to the vertebrae.
What are the main contents of the superior mediastinum?
- Arch of the aorta, and its three branches.
- Superior vena cava, left and right
brachiocephalic veins. - Trachea.
- Oesophagus.
- Phrenic nerves and vagus nerves.
- Thoracic duct.
- Thymus gland.
What are the three parts of the aorta? Describe them and their locations.
- Ascending aorta: short, first part. Gives rise
to coronary arteries, which supply the
myocardium. - Arch of the aorta: curves posteriorly. Lies in
the superior mediastinum. - Descending (thoracic) aorta: descends
through posterior mediastinum and into the
abdomen posterior to the diaphragm.
What are the three major branches that the arch of the aorta gives rise to?
- The brachiocephalic trunk, bifurcates ->
right common carotid artery (supplies right
side of head, neck and brain), and right
subclavian artery (supplies right upper limb). - Left common carotid artery (supplies left
side of head, neck and brain). - Left subclavian artery (supplies left upper
limb).
Which receptors can be found in the aortic bodies in the arch of the aorta? What do they do?
- Chemoreceptos which monitor arterial
oxygen and CO2. - Visceral sensory info -> CNS via vagus nerve,
resulting in reflex responses that regulate
ventilation.
What is the ligamentum arteriosum?
- Fibrous, cord-like connection between
pulmonary trunk and the arch of the aorta. - Remnant of ductus arteriosus (fetal
circulatory shunt).
Describe the superior vena cava.
- Returns blood to the heart from the head,
neck and upper limbs. - Lies in superior mediastinum.
- Formed by left and right brachiocephalic
veins, which are each formed by the unions
of internal jugular veins and subclavian
veins.
Describe the inferior vena cava.
- Returns blood to the heart from all regions
inferior to the diaphragm. - Thoracic part is very short, entering the right
atrium as soon as it enters the thorax.
Describe the trachea.
- Conducts air to and from the left and right
main bronchi. - Semi-rigid due to C-shaped rings of cartilage
in its walls. - Extends from the larynx in the neck to the
superior mediastinum. - Palpable superior to the suprasternal notch.
- Terminates at level of sternal angle/ T4 and
T5 junction, bifurcates -> left and right main
bronchi.
Describe the oesophagus, in relation to the superior mediastinum.
- Muscular tube extending from phaynx in the
neck to the stomach. - Waves of smooth muscle contractions move
food and fluid distally (peristalsis). - In the superior mediastinum it lies
posteriorly to the trachea.
Describe the phrenic nerves.
- Formed by fibres from C3 -> C5 spinal
nerves, innervate the diaphragm. - Somatic nerves containing motor and
sensory fibres. - Descend through neck, enter thorax
through superior thoracic aperture, course
over pericardium, and pierce the
diaphragm.
Describe the vagus nerves.
- CN X.
- Arise from brainstem; contain somatic
sensory and motor, and parasympathetic
fibres. - Descend through neck alongside internal
carotid artery and internal jugular vein,
enter thorax via superior thoracic aperture. - Each give rise to a recurrent laryngeal nerve,
ascend back up to neck to innervate larynx
muscles. - Vagus nerves descend in thorax posterior to
root of the lung. - Contribute parasympathetic fibres to heart,
lungs, and oesophagus. - Traverse the diaphragm, conveying
parasympathetic fibres to most abdominal
viscera.
Describe the thoracic duct, in relation to the superior mediastinum.
- Major channel for lymphatic drainage.
- Ascends through posterior mediastinum,
into the superior mediastinum, where it
empties into venous system at the union of
the left internal jugular vein and left
subclavian vein.
Describe the thymus gland.
- Lymphoid organ.
- Lies anteriorly in the superior mediastinum.
- Important in children, atrophies with age.
Describe the pericardium.
- Tough, fibrous sac, enclosing the heart like a loose-fitting bag, with 2 layers.
- Tough, outer fibrous layer: attached
superiorly to the great vessels, and inferiorly
to the central tendon of the diaphragm. - Thin, inner serous layer, made up of 2 parts:
parietal layer lining the inner aspect of the
fibrous pericardium, and the visceral layer
covering the surface of the heart (2 parts are
continuous with each other).
What is the space between the two serous layers of pericardium? What does it contain and what does it do?
Pericardial cavity, contains small amount of pericardial fluid. Lubricates the membranes allowing them to slide over each other with movement of the heart.
What are some of the clinical relevancies of the superior mediastinum and the external heart?
- Patent ductus arteriosus (PDA).
- Hoarseness of the voice and lung cancer.
- Pathology of the pericardium: pericardial
effusion and cardiac tamponade.
What are the main branches of the right coronary artery (RCA), and what territories do they supply?
- Branches to sinoatrial node and
atrioventricular node, supplying these major
components of the electrical conducting
system of the heart. - Right marginal artery, supplies inferior
border of the heart. - Posterior interventricular artery, which is
continuation of the RCA on the inferior
surface of the heart, supplies both
ventricles.
What are the main branches of the left coronary artery (LCA), and what territories do they supply?
- Short course = left main stem -> two large
terminal branches: - Anterior interventricular artery / left anterior
descending artery (LAD): runs in anterior
ventricular sulcus towards the apex,
supplies both ventricles. - One/two diagonal branches arise from LAD.
- Circumflex artery: around the heart onto the
inferior surface, supplies left atrium, part of
the right ventricle, and the left ventricle. - Left marginal artery arises from circumflex,
supplies left ventricle.
Describe right-dominant coronary circulation.
- Posterior interventricular artery arises from the right coronary artery.
- Both the right and left coronary arteries supply the left ventricle.
- Occlusion of the left main stem would only impair blood flow to part of the left ventricle, not all of it.
Describe left-dominant coronary circulation.
- Posterior interventricular artery arises from
circumflex artery. - Left coronary artery supplies the entire left
ventricle. - Occlusion of the left main stem would
occlude blood flow to the entire left
ventricle.
Describe the right atrium.
Receives deoxygenated blood from the body via the superior and inferior vena cavae, and from the heart via the coronary sinus.
Contains:
- Interatrial septum: separates from left
atrium.
- Fossa ovalis - depression in the interatrial
septum, remnant of fetal foramen ovale.
- Crista terminali - muscular ridge separating
smooth-walled posterior, and
muscular-walled anterior (pectinate muscles
= ridges).
- Thinner walls then ventricles.
Describe the right ventricle.
Receives deoxygenated blood from the right atrium via the right atrioventricular valve, aka the tricuspid valve. Mostly passive, but the left atrium does contract to empty fully.
Contains:
- Interventricular septum: separates from left
ventricle.
- Trabeculae carneae: muscular ridges on
internal wall.
- Papillary muscles: modified regions of
trabeculae carneae.
- Chordae tendineae: fibrous cords with
connect tips of papillary muscles -> tricuspid
valve.
- Moderator band - modified region of
trabeculae carneae, connect interventricular septum -> one of the papillary muscles.
- Thicker walls than atria.
Pumps deoxygenated blood -> pulmonary trunk -> bifurcates to left and right pulmonary arteries.
Describe the left atrium.
Receives oxygenated blood from the lungs via the pulmonary veins (two from each lung).
Contains:
- Likewise structures to the right atrium.
- Thinner walls than ventricles.