Thorax Flashcards
What are the differences between the ribs?
Ribs 1-2 are mostly flat and are irregularly bumpy.
Ribs 3-10 are more gently curved and their costal heads+tubercles project notably.
Ribs 11-12 are floating. NOT CONNECTED to sternum. Subtle tuberosity.
What part of the sternum starts out as cartilage?
All of it, but the xiphoid process takes much longer to ossify.
Which ribs have their own costal cartilage?
Ribs 1-7 attach to the sternum with their individual costal cartilages.
Ribs 8-10 attach to the costal cartilage of 7.
Ribs 11-12 have costal cartilage but it is NOT connected to the sternum.
What sits between the articulation of the clavicle and the manubrium?
An articular disc.
What ligament and muscle is attached to rib 1 near the sternum?
Subclavius muscle
Costoclavicular ligament
What ligaments do I find on the rib near the vertebrae?
Radiate ligament between the rib and the vertebrae.
Costotransverse, lateral costotransverse ligaments, and superior costotransverse ligaments between the neck of a rib to the transverse process at the same level and above.
How do the ribs move during inspiration?
Ribs 1-2 anteriorly
Ribs 3-10 open laterally (like a bucket handle)
Ribs 11-12 open laterally like pincers
Sternum moves superiorly
What muscle covers the rectus abdominis and serratus anterior?
External Abdominal Obliques
What groove would I find my cephalic vein in?
Deltopectoral
What nerve innervates my serratus anterior?
Long thoracic nerve
What artery supplies my serratus anterior?
Lateral thoracic artery
What artery supplies my external intercostal muscles?
Superior thoracic artery for ribs 1-2
ascending aorta for the rest
Where do my external intercostals originate from, insert at, and what direction are they going?
Originating at the vertebrae, they go INFEROMEDIALLY (like hands in a pocket) to the sternum.
What do the external intercostals become at the sternum?
External intercostal membrane
Where do my internal intercostals originate from, insert at, and what direction are they going?
Originating at the sternum, they go SUPEROMEDIALLY to the vertebrae.
What do the internal intercostals become at the vertebrae?
Internal intercostal membrane
Where do I find innermost intercostal muscles specifically?
Parallel to my internal intercostals, but only in the lateral portion of my ribs.
What muscles extend from my sternum directly to my ribs and cartilage?
Transversus thoracis
What three vessels/tubes travel through my diaphragm?
Aorta, Inferior vena cava, esophagus.
What does the diaphragm originate and insert at?
Originates from the xiphoid process, attaching to the T12 and upper lumbar vertebrae
What nerve innervates the diaphragm and what is the nerve a combination of?
Phrenic nerve
C3,4,5 keep the diaphragm alive
What muscles are used in inspiration?
Diaphragm
External intercostals
Internal intercostals (parasternal)
Scalene
What muscles are used in normal expiration?
Just the diaphragm
What muscles are used in heavy/forced expiration?
Diaphragm
Internal intercostals (lateral portion)
Innermost intercostals
Abdominal obliques
Rectus abdominis
Transversus thoracis
What is the purpose of the extrinsic back muscles in relation to breathing?
Stabilizing/fixing the scapula in place so our other muscles can move just our ribcage.
What muscles elevate ribs 1-2?
Scalenes (mainly anterior?)
What muscles elevate our anterior ribcage? What condition must be met?
Pectoralis major and minor.
The scapula must be fixed/stabilized by the back muscles.
What muscles elevate our lateral ribcage? What condition must be met?
Serratus anterior.
The scapula must be fixed/stabilized by the back muscles.
What muscles tend to hypertrophy in patients with COPD?
Inspiratory muscles
What supplies the thoracic wall with blood?
Intercostal arteries, which originate from the internal thoracic artery and aorta
What kind of branches do intercostal nerves and arteries have?
anterior and lateral cutaneous branches.
What are the 3 major branches off the arch of the aorta?
Brachiocephalic trunk
Left common carotid artery
Left subclavian
Where do intercostal veins drain to?
Internal thoracic veins anteriorly
Azygos system posteriorly
Note: azygos means unpaired
Explain the difference between the left and right venous drainage of the ribs?
The right side uses a single azygos vein which drains to the superior vena cava.
The left side has a hemiazygos vein (lower left intercostal veins and left ascending lumbar veins). The hemiazygos goes to the azygos & accessory hemiazygos veins.
It also has a accessory hemiazygos vein (upper left intercostal veins & left brachiocephalic vein)
Note: *Only pattern used for the exam per his email.
Superiorly to inferiorly, describe the order of the artery, vein and nerves.
Vein
Artery
Nerve
However, they give a small branch that runs within the same intercostal space, which goes nerve, artery, vein.
Clinical: If I wanted to perform a thoracocentesis (inserting a needle into the thorax for drainage), where should I poke?
In the center of an intercostal space. Veins, Nerves, and Arteries run along the superior and inferior grooves of a rib.
Confirmed per Dr. Ward email
Note: This is for MIDAXILLARY and example showed 9th intercostal specifically.
*Emailed Dr. Ward regarding this
Clinical: If I wanted to perform a intercostal nerve block where should I poke?
Slighty superior or inferior from the center of an intercostal space. Nerves are closest to the center of the intercostal space.
Note: The example in class was in the 9th intercostal space.
What is the center of the thoracic cavity known as?
Mediastinum
What makes up the inferior borders of my superior mediastinum?
Sternal angle anteriorly
T4-T5 posteriorly
What is in my superior mediastinum?
The great vessels (superior vena cava, brachiocephalic veins, aortic arch)
Nerves (Vagus, Phrenic, Left recurrent laryngeal)
Thoracic duct
Trachea
Esophagus
Thymus
Great Sushi Bar Ay? No, Very Poor Lemonade. Think That Every Time -Billie
What is in my anterior inferior mediastinum?
Thymus, Lymph nodes, and fat/connective tissue.
What is in my middle inferior mediastinum?
Pericardium and heart
Roots of great vessels
Arch of azygos vein
Primary Bronchi
What is in my posterior inferior mediastinum?
Esophagus
Aorta
Azygos & hemiazygos veins
Thoracic duct
Vagus nerves
Sympathetic trunk
Splanchnic nerves
Where is the thymus found primarly?
Superior mediastinum.
What does the superior vena cava branch into?
The left & right brachiocephalic veins.
What ligament connects the aortic arch and the pulmonary trunk?
Ligamentum Arteriosum
What is more superior, the aortic arch or the primary bronchi?
Aortic arch
What lobules do I find more superiorly in the breast?
Fat lobules
What lobules do I find more inferiorly in the breast?
Lactating mammary gland lobules.
Describe the path of milk in the breast.
Milk is made in the lactating mammary gland lobules, going to the lactiferous ducts, then to the lactiferous sinuses, which eventually drain at the nipple.
What ligaments attach the lobules to the chest wall?
Suspensory ligaments (of cooper)
What is the space called between the breast and the pectoralis major?
Retromammary space.
What are some signs of breast cancer?
Orange peel sign
Breasts adhering to the chest wall
What vessels supply the breast with blood?
Internal thoracic and lateral thoracic, with small contributions of the lateral cutaneous branches of the intercostal artery and vein.
What is the predominant path of lymph flow in the breast?
Lateral and central -> interpectoral -> axillary (pectoral nodes)
This accounts for ~75% of lymph flow
What is the minor path of lymph flow in the breast?
Medial -> parasternal nodes to the opposite breast
What makes up the right border of the heart?
Superior vena cava
Right atrium
Inferior vena cava
Right auricle
What makes up the inferior border of the heart?
Primarily the right ventricle
What makes up the left border of the heart?
Left ventricle
Left auricle
What makes up the superior border of the heart?
Left atrium
Right atrium
Where is the fossa ovalis?
Found in each atrium.
Note: important in embryological development
What is the crista terminalis and where is it found?
Found in the right atrium near the right auricle, a common location for pacemakers.
Where are pectinate muscles found?
Along the walls of the atrium.
Where do I find papillary muscles? What is attached to them?
Found only in the ventricles, they have chordae tendineae coming off them, connecting to the AV valves.
What is the moderator band, where do I find it?
Found in the right ventricle, going across the inferior aspect. It is part of the electrical system of the heart.
Where do I find the pulmonary semilunar valves?
In between the pulmonary artery and right ventricle.
How many ostia are there for coronary arteries?
1 for each coronary artery, so 2.
They drain right above the aortic semilunar valves.
Where is the ostium for the coronary sinus located?
Right Atrium
What are the 3 functional layers of the heart?
Epicardium
Myocardium
Endocardium
What is the most muscular part of the heart?
Left Ventricle
What is the function of the epicardium?
It has a serous lining that releases lubricating fluid.
Inferior to the lining is adipose tissue, followed by coronary vessels.
What are some of the key differences between skeletal and heart muscle?
Heart muscle contains intercalated discs, which connect the cytoplasm of each cell to create a syncytium.
Cardiac myocytes also have central nuclei, not peripheral.
What are the 3 layers of endocardium?
Endothelium
Subendothelial connective tissue
Subendocardium
What is the endothelium of the endocardium? Purpose?
It is a simple squamous epithlium with basal lamina, continuous with the vessel endothelium.
It can help prevent clots and release hormones when it is stretched.
What is the subendothelial connective tissue made of? What does it make up?
Dense irregular CT (connective tissue), aka collagen.
It helps form the chordae tendineae and the valves.
What is the subendocardium?
A CT layer next to the myocardium that contains small vessels and nerves for the myocardium.
What is the conduction pathway of the heart, beginning at the top?
SA node goes to each atria and the AV node.
The AV node goes to the Bundle of His, which splits into the left/right bundle branches (purkinje fibers)
The bundle branches then go to each ventricle.
What best describes how a heart contracts (the physical appearance)?
Wringing out, like a towel. More effective than simply squeezing.
What is the fibrous skeleton and what is its purpose?
Insulating CT that isolates the atria from the ventricles electrically.
Ultimately prevents APs from passing from atria to ventricle (so they don’t contract at the exact same time)
Where do I find the fibrous skeleton of the heart?
Major vessels, AV canals, and upper portion of the interventricular septum.
What part of contraction are AV valves closed?
Systole
What part of contraction are Semilunar valves closed?
Diastole
Where do coronary arteries originate from?
Aorta.
What is the mnemonic for the semilunar valves?
LARP
Left, anterior, Right, (Pulmonary artery)
Left, (Aorta), right, posterior
What are the 4 locations to listen to heart valves?
Aortic: 2nd right intercostal near sternum
Pulmonary: 2nd left intercostal near sternum
Tricuspid: 5th left intercostal near sternum
Bicuspid: 5th left intercostal in midclavicular
What are the main branches of the right coronary artery?
SA nodal branch (60%)
Right marginal branch
Posterior right ventricular branch
Posterior interventricular branch
What are the main branches of the left coronary artery?
Circumflex branch
Anterior interventricular branch (Also known as LAD, or left anterior descending)
Left marginal branch
Diagonal branches
Septal branches
Posterior left ventricular branch
What normally supplies the posterior interventricular artery? What do we call this?
85% of the time, it is the RIGHT coronary artery. We call this a right dominant heart.
What are the main veins that drain the heart itself?
Coronary sinus -> Right Atrium
Middle cardiac vein (descends to the apex posteriorly)
Small cardiac vein (goes posteriorly, following the right coronary artery)
Great cardiac vein (goes anteriorly, following the left anterior descending)
Note: some anterior veins can drain straight into the right atrium.
Describe what the ascending aorta supplies.
Coronary arteries, which supply the heart.
Describe what the aortic arch supplies.
Brachiocephalic trunk, containing the right common carotid and right subclavian.
Left common carotid
Left Subclavian
Describe what the descending aorta supplies.
Intercostal and lumbar branches -> body wall.
Unpaired branches, including:
Celiac trunk: foregut
Superior mesenteric artery: Midgut
Inferior mesenteric artery: Hindgut respectively
Paired branches, including:
Renal arteries
Gonadal arteries
Describe what the common iliac arteries supply.
Internal iliac arteries have anterior/posterior branches, going to the pelvic viscera and muscles.
External iliac arteries go to the lower limbs.
What are the 3 layers of a blood vessel?
Inferior to exterior:
Tunica intima
Tunica Media
Tunica adventitia
What is the tunica intima made of?
Endothelium and subendothelial CT
What is the tunica media made of?
Smooth muscle
Elastic fibers (only in large vessels)
What is the tunica adventitia made of?
Dense irregular CT with some elastic fibers.
What is a unique characteristic for a large vessel’s tunica adventitia?
Their own blood vessels, called vasa vasorum.
Large nerves have nervi vasorum.
Where do I typically see inflammation due to fatty deposits in a blood vessel? (Layers)
Tunica intima and media
Clinical: What does arteriosclerosis cause?
Inflammation in the tunica intima and media, damaging their walls and allowing clots to form and embolize.
What is restenosis?
A vessel become stenosed again, aka becoming stiffer.
This is due to smooth muscle cell proliferation POST angioplasty or stent.
What is an aneurysm?
A ballooning of an artery, typically due to arterial wall weakness.
Often associated with:
arteriosclerosis
syphilis
CT disorders (EDS, Marfan’s)
What do arteries experience that veins do not?
Immense pressure. Arteries must therefore be tougher and more elastic.
What is distinct about capillary walls?
No discernable tunica media or adventitia. They have a single layer of endothelium but remnants of the other layers anchor capillaries in the ECM.
They are surrounded by a thin sheath made up of reticular and collagen fibers.
Describe the walls of a continuous capillary. Where are they found?
Continuous endothelium and basal lamina.
Found in the CNS and most of the body.
Contributes to the blood brain barrier.
What other parts of the body have a blood barrier besides the CNS?
Thymus: prevent autoimmune attacks
Testes/Ovaries: prevent self-recognition
Describe the walls of a fenestrated capillary. Where are they found?
Thin endothelium with large openings covered by basal lamina.
Found in the GI tract, endocrine glands, kidneys, choroid plexus, and ciliary body.
Describe the walls of a sinusoidal capillary. Where are they found?
Irregular walls, wide gaps between cells, large fenestrations, and an incomplete basal lamina.
Found in the liver and other hematopoietic organs (spleen, liver, bone marrow)
Describe the transition of a capillary to a vein.
Capillary => venule => muscular vein
What makes veins different from arteries wall-wise?
Muscular veins have more smooth muscle and valves. They have to prevent retrograde blood flow or stagnation of blood flow. They contract to push the blood back to the heart, since they lack left ventricular force.
What are vein valves an extension of?
They are semilunar and paired folds of intima.
What two things help blood flow in veins?
The smooth muscle of the vein
Muscular compression
Clinical: Why are varicose veins bad?
They are excessively dilated veins that are a result of decreased muscle tone and/or venous valve failure.
Blood pools and thromboses much easier in these veins.
Clinical: What is a deep venous thrombosis (DVT)? Why is it bad? Signs?
A thrombus forming within a vein, often in the lower extremities due to blood stagnation or trauma. They often cause edema.
However, the clinically significant issue is that when they break loose, they can cause a pulmonary embolism, which is life-threatening.
What is the inelastic covering of the heart?
Pericardium
What is the pericardial fold that separates outflow and inflow vessels of the heart? Clinical signficance?
Transverse pericardial sinus, found under the aorta and pulmonary artery.
Vital landmark during cardiac surgery.
Note: The oblique pericardial sinus is another landmark, found under the transverse pericardial sinus.
What are the two layers of the parietal pericardium?
Fibrous pericardium (external) (also same function as the epicardium in secreting fluid.)
Serous pericardium (inner)
Note: They are fused, unlike the lungs.
Clinical: What is cardiac tamponade? What are the 3 major signs?
Any fluid that fills the INSIDE of the pericardium. Because the pericadium is inelastic, the fluid compresses the heart, AKA tamponading it. As it fills up, the heart has difficulty expanding and beating properly, so it gets weaker and weaker.
Beck’s triad:
Low BP
Weak heart valve sounds
JVD (jugular vein distension), which you can see in someone’s neck.
Describe the layers of the respiratory tract from deep to superficial.
Air
Epithelium
Lamina propia
Muscularis
Submucosa
Cartilage (sometimes)
Adventitia
What tissue/epithelium covers most of the respiratory tract?
Pseudostratified ciliated columnar epithelium.
What are the cells contained within the respiratory epithelium?
Ciliated cells - move mucus
Goblet cells - create mucus
Small granule cells - endocrine
Brush cells - sensory
Basal cells - stem cell population
What is the function of the conducting zone of the lungs?
Conducting, moistening, and filtering air.
Starts at the nasal cavity, going down to the bronchioles.
What is the function of the respiratory zone of the lungs?
Gas exchange, alveoli only
What kind of epithelium does our nasopharynx have?
Pseudostratified ciliated columnar, same as the respiratory tract itself.
What is the difference between the two vocal folds in terms of epithelium?
False has respiratory epithelium covering loose CT.
True has non-keratinized stratified squamous epithelium, covering dense CT+muscle.
What are the layers of the trachea?
Mucosa:
Respiratory epithelium
Lamina propia
Muscularis
Submucosa:
Cartilage (C-shaped to help the airway open)
Glands
Adventitia
Clinical: What cell population gets increased in the airway if it is chronically irritated?
Goblet cells, which secrete mucus.
Which bronchi goes more vertical?
Right (Left one has the heart under it!)
How many secondary bronchi do we have?
3 Right, 2 Left (One for each lobe)
How many tertiary bronchi do we have?
10 Right, 8 Left
Note:
We have 10 segments within our right lobe, hence 10 tertiary bronchi.
What do all bronchi have in common in their walls?
Lined by respiratory epithelium
Cartilage plates and smooth muscle
What is unique about the left lung?
2 lobes only
Each lobe has 5 segments.
Each lobe has a pair of segments supplied by the same tertiary bronchi (hence 8 tertiary bronchi)
Clinical: What are the 3 types of lung surgeries that remove lung tissue?
Segmentectomy (single segment)
Lobectomy (single lobe)
Pneumonectomy (single lung)
Where do bronchial arteries come from?
Aorta
Where do bronchial veins drain to?
Azygos vein and accessory hemiazygos vein
What makes a bronchial artery distinct from a pulmonary vein location wise?
Bronchial arteries run along the actual bronchi.
Pulmonary veins go solely to alveoli.
What is the difference between bronchi and bronchioles?
Bronchioles lose the glands and cartilage plates, so they are made up of just smooth muscle.
Their ciliated columnar cells get shorter, turning into ciliated cuboidal cells.
Their globlet cells are called bronchiolar exocrine (clara) cells.
Bronchiolar exocrine cells secrete glycosaminoglycans, preventing collapse of the smaller airways and releasing ions into the lumen.
What are the defining features of alveolar ducts?
They have a simple squamous epithelium made of type I and type II pneumocytes.
Last portion of the respiratory system containing smooth muscle.
What separates alveoli from each other?
type I and type II pneumocytes separated via extremely thin interalveolar septa.
Describe a type I pneumocyte.
Flat pneumocytes that make up 40% of all pneumocytes, but cover 95% of the alveolar surface.
They allow gas diffusion through their cytoplasm.
Note: They look smaller than type II pneumocytes, like flat raisins.
Describe a type II pneumocyte.
Larger and rounder pneumocytes that make up 60% of all pneumocytes. They cover only 5% of the alveolar surface.
They are the precursor to BOTH types of pneumocytes, as they can divide and regenerate.
They release surfactant.
Describe the 3 layers of interalveolar septa.
Type I pneumocyte and thin coating of surfactant
Basal lamina of pneumocytes and capillary cells fuse
Capillary cells (endothelium)
Note: They are 0.2 micrometers or less thick.
What kind of capillary would I find in interalveolar septae?
Continuous capillaries, since they are there for gas exchange.
What are alveolar macrophages?
Dust cells that remove ultra-fine debris from the airway.
“Full” ones can migrate into the lumen to go up to the pharynx.
Increased from inflammation and some heart failures.
Clinical: Describe what asthma is and its usual cause.
Excessive constriction of BRONCHIOLES.
Bronchioles have smooth muscle, so they can inflame.
Symptoms: Difficult expiration, mucus in airways, inflammatory cell infiltration
Cause: allergens, which trigger mast cells.
Tx: Bronchiolar smooth muscle relaxants, such as beta-2 agonist drugs.
Clinical: Describe what cystic fibrosis is and its usual cause.
A disease causing abnormally thick mucus in the airways and other organs.
Cause: Cl- pump mutation, which prevents H2O from coming to thin the mucus out.
Symptoms: Thick mucus, high rate of infections, asphyxiation
Clinical: Describe what emphysema is and its usual causes.
A disease causing the destruction of the elastic fibers of the interalveolar septae (aka destroying the alveolar walls)
Results in decreased surface area and loss of elasticity.
This means gas exchange is reduced and the alveoli lose some recoiling.
Cause: Genetic deficit in alpha1 antitrypsin.
OR
Smoking/inhaling something that causes inhibits alpha1 antitrypsin.
Clinical: Describe what silicosis is and its usual cause.
A disease causing inflammation in the lungs from nodules.
Inflammation can result in progressive damage that is usually irreversible and terrible. (Pneumoconiosis)
Nodules are formed from the particles causing inflammatory reactions.
Cause: Inhaling silicon/fine sand particles
Clinical: What is ARDS? What do we call it on a cellular level? Causes?
Acute respiratory distress syndrome.
Cellularly: Diffuse Alveolar Damage (DAD)
Results in damage to pneumocytes, alveolar septae, and vessels. Fibroblasts also come and create CT in lung parenchyma, thickening the septae and impeding gas exchange:
Causes: SARS, SARS-CoV-2, Sepsis
What is the difference in lung anatomy between the right and left?
Left has 2 lobes, superior and inferior separated by the oblique fissure. Also has a cardiac notch.
Right has 3 lobes, superior and inferior separated by the oblique fissure. Middle lobe is separated by the oblique fissue and the horizontal fissure.
What lines the thoracic cavity and lung surfaces?
Pleura.
Visceral pleura on the lungs, parietal pleura closer to the thoracic cavity.
What is it called when blood gets into the pleural space? Air? Lymph?
Hemothorax
Pneumothorax
Chylothorax
How do we name the pleura of the thoracic cavity?
The surface they cover, such as Cervical pleura, or costal pleura, or mediastinal pleura.
What is the key difference between the pleura of the lungs and the pericardium?
The pleura of the lungs is actual one continuous layer, whereas the pericardium is two fused layers.
What part of the thoracic cavity has no pleura?
Mediastinum
How high does the apex of the lung reach?
Higher than the first rib, so neck trauma can damage the lungs.
What are the landmarks of the line of pleural reflection?
Anterior: 8th costal cartilage
Lateral: 10th rib
Posterior: 12th rib
What are the landmarks of the inferior border of the lungs?
Anterior: 6th costal cartilage
Lateral: 8th rib
Posterior: 10th rib
What is the space between the inferior border of the lungs and the line of pleural reflection called?
Costodiaphragmatic recess
Clincal: Where is the best location for a thoracocentesis?
Between the 8th and 10th ribs LATERALLY.
Per Dr. Ward, aim for the center of the intercostal space.
Avoid inferior and inferior aspects due to the large intercostal bundles.
Note: Example showed 9th intercostal space specifically.
*Emailed Dr. Ward about this
Describe the lymphatic drainage of the lung.
Lungs go to pulmonary nodes => hilar nodes.
Hilar nodes can go to both inferior and superior tracheobronchial nodes, but inferior ultimately go to superior ones.
Superior tracheobronchial nodes => paratracheal nodes.
Paratracheal nodes can either go to the inferior deep cervical nodes (usually for pre-tracheal nodes) or the bronchomediastinal trunk, which goes straight to the subclavian.
Inferior deep cervical nodes => supraclavicular nodes => jugular lymph trunk => subclavian vein
Describe the lymphatic drainage of the heart.
Mimics the lungs, except for the first two nodes.
Heart => subepicardial lymph plexus => coronary lymph vessel => same path as lungs with the inferior and superior tracheobronchial nodes.
