Chapter 19: Thorax and Lungs

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Welcome to a very special edition of the Deep Dive.

Yeah, today we're bringing you a dedicated Last Minute Lecture edition.

Right, so if you're listening to this, you're not just here for a casual overview of the news.

No, you are a nursing student.

Exactly.

And you are getting ready to master Chapter 19 on the thorax and lungs from your physical examination and health assessment textbook.

We are tailoring this entire session specifically for you.

We have a very focused mission today.

We're going to walk through this material in the exact order it appears in your text.

But we aren't just going to memorize a list of symptoms or anatomical terms.

We really want to understand the why behind them.

Yeah, there's a beautifully logical flow to how this chapter is laid out.

There really is.

We'll look at how understanding foundational anatomy directly supports your interview skills.

And how those interview clues guide your physical exam.

Right, which ultimately leads you to a safe clinical interpretation and excellent patient care.

So as your study guides today, we're going to be talking directly to you.

We're keeping things conversational, supportive,

and, you know, completely free of any overwhelming medical jargon that isn't clearly explained.

Let's start by looking at the foundational concepts and structure of the chest.

The book begins by emphasizing landmarks.

Right.

If I'm looking at a patient's anterior chest,

the front,

how do I even begin to navigate where I am?

Well, think of those landmarks as the physical signposts on your patient's chest.

Okay.

They help you localize a finding so you can communicate it accurately to the rest of the medical team.

So on the front, you start by finding that hollow U -shaped depression just above the breastbone, right between the collarbone.

Yes, that is the suprasternal knot.

And if you walk your fingers down the breastbone, the manubrium, just a few centimeters, you'll feel a very distinct bony ridge.

I'm glad you brought that up.

The text heavily emphasizes that ridge, calling it the sternal angle or the angle of Louis.

Why is that specific spot so crucial for a nurse to find?

I mean, why that ridge?

The angle of Louis is your golden starting point for two major reasons.

Okay, what's the first?

On the outside of the chest, it's the exact spot where the second rib attaches.

Oh, so from there, you can easily start counting the ribs down the middle of the hemothorax without getting lost.

Exactly.

But if we think about what's happening inside the body at that exact same level, the angle of Louis marks the site where the trachea bifurcates.

Which means it's the exact spot where the main windpipe splits into the right and left main bronchi.

You got it.

That makes a lot of sense.

So that maps out the front.

What about when we ask the patient to sit forward so we can examine their back, the posterior chest?

On the back, you ask the patient to flex their head forward, touching their chin to their chest.

Right.

And when they do that, you'll feel a prominent bony spur sticking out at the base of their neck.

That's the vertebra prominence, technically the C7 vertebra.

And that serves as your starting point for the posterior chest.

Right.

From that spur, you just count the knobs of the spinous processes straight down the spine.

Now that we have the outside mapped, let's look at the actual lungs inside.

This is where it gets a little tricky.

Yep.

The text points out three major things about the lobes of the lungs that tend to confuse

beginners, mostly because the lungs aren't perfectly symmetrical.

They really aren't.

The first confusing point is that the left lung has no middle lobe.

It only has two lobes, an upper and a lower.

Right.

As the right lung has three.

The reason for this asymmetry is simply a matter of real estate, isn't it?

Exactly.

The left lung is narrower because it has to make room for the heart, which bulges over to the left side of the chest cavity.

Okay.

So the second point is about what we are actually hearing when we listen to the front of the chest.

The text notes that the anterior chest contains mostly the upper and middle lobes.

And that leads directly to the third and probably most clinically important point.

The posterior chest is almost entirely made up of the lower lobes.

Yes.

The upper lobes only occupy a tiny band at the very top of the back, down to about the level of T3 or T4.

And the entire rest of the back is all lower lobe.

Which means if a nurse is rushing and only listens to a patient's front, they're completely missing the lower lobes.

That is a huge takeaway.

It really is.

If a patient has a respiratory infection, fluid and pneumonia tend to settle by gravity into the lower lobes.

So if you aren't listening to the back, you aren't listening to the lower lobes, and you can easily miss a critical finding.

Exactly.

Let's talk about how these lungs actually move.

The text describes the pleurae, which surround the lungs.

It uses this great analogy of two wet glass slides pressed together.

I love that analogy.

You can slide them back and forth smoothly against each other, but if you try to pull them straight apart, it's incredibly difficult.

That is a perfect mental model for the pleurae.

It's a smooth, double -layered envelope.

Right.

One layer is attached to the lung, the other to the inside of the chest wall.

Inside that envelope is a tiny amount of lubricating fluid and crucially, a vacuum of negative pressure.

That negative pressure is what holds the lungs tightly against the chest wall, so they don't collapse.

And as the air moves into those expanding lungs, it travels down the trachea and the bronchi.

The text refers to this area as dead space.

We call it dead space because it holds about 150 milliliters of air, but no actual gas exchange happens there.

It's just the transport highway.

Exactly.

The real work happens at the end of the line, in the acinus.

The acinus is where the alveoli are, right?

I've always pictured them clustered together like tiny microscopic bunches of grapes.

That bunched, grape -like arrangement is incredibly efficient.

Because instead of the lung being one big empty balloon,

millions of those tiny, grape -like walls drastically increase the available surface area.

If you flattened out all the alveoli in a human lung, the surface area for gas exchange would be about the size of a tennis court.

A whole tennis court.

Yeah.

All folded and packed inside the chest.

That's wild to visualize.

And to fill that tennis court with air, the mechanics of respiration rely on two main movements.

Right.

The text explains that the chest cavity expands vertically when the diaphragm muscle contracts and pushes downward.

Then it expands anteriorly, posteriorly, or front to back when the rib cage elevates.

So you have this 3D expansion happening with every single breath, pulling air into that massive surface area.

Knowing how all of that works really sets the stage for gathering our subjective data, the health history interview.

Because before we ever put a stethoscope on a patient, we are listening to their story.

So what are the key symptoms a nurse should be asking about to guide the physical exam?

You always start by asking about a cough.

But you need to dig into the timing.

How so?

If a patient has a continuous cough throughout the day, you're likely looking at an acute illness, like a sudden respiratory infection.

But if the cough primarily happens at night, that could be post -nasal drip.

Exactly.

When they lie down flat, the sinus drainage drips back and irritates the throat.

Conversely, an early morning cough is a classic hallmark of chronic bronchial inflammation, which is very common in smokers.

We also need to ask about shortness of breath, or SOB.

The book emphasizes that we can't just ask, do you get out of breath?

We need to measure the severity.

Precision is everything here.

You want to ask exactly how many blocks they can walk, or how many stairs they can climb before they're forced to stop and catch their breath.

You also need to screen for a condition called orthopnea.

Orthopnea is difficulty breathing when lying completely flat.

And you document its severity by asking how many pillows the patient needs to prop themselves up to sleep comfortably.

Right, so you might chart two -pillow orthopnea.

The text also mentions paroxysmal nocturnal dyspnea.

That sounds terrifying for the patient.

It is very distressing.

Paroxysmal nocturnal dyspnea is when a patient wakes up from sleep suddenly gasping for air and needs to sit upright immediately to breathe.

Why does that happen?

It happens because when they lie flat for a few hours, fluid from their lower extremities shifts back into their core, overloading their cardiovascular and respiratory systems.

Wow.

We also have to ask about chest pain.

But we need to differentiate pleuritic pain from cardiac or gastrointestinal pain.

How does a nurse tell the difference just by asking questions?

Well, pleuritic pain is directly tied to the mechanics of breathing we talked about earlier.

If the pleurae are inflamed, those two wet glass slides aren't sliding smoothly anymore.

They're rubbing like sandpaper.

So pleuritic pain gets sharply worse with deep breathing or coughing.

Whereas cardiac pain usually feels more like a heavy pressure that isn't changed by taking a breath.

Once we map out those symptoms, the interview moves into history and risk factors.

Assessing a patient's smoking history is standard, and we calculate their pack years.

By multiplying the number of packs they smoke a day by the number of years they've smoked.

And if they do smoke, patient -centered care means asking if they are ready to quit.

If they are, evidence -based guidelines say the nurse should offer the 5As ask, advise, assess, assist, and arrange.

That provides structured help for quitting.

The text also highlights asking about environmental exposures, like working around asbestos or breathing heavy traffic exhaust daily.

Plus, we check on their basic health promotion, asking about their last TB test, their annual flu shot, and their COVID -19 vaccines and boosters.

You should also ask if they've had any recent COVID -19 symptoms, specifically things like a sudden loss of taste or smell.

We also have to adapt our interview for the aging adult.

For older patients, you want to ask specifically about fatigue during normal daily activities.

As the body ages, the respiratory system naturally becomes less efficient.

The chest wall gets stiffer, and they lose some of that tennis court surface area in the alveoli.

Less surface area for gas exchange means older adults simply have less tolerance for strenuous activity.

So we've gathered all these verbal clues from the patient.

Now it's time to actually lay hands on them.

Where does a nurse even begin with the physical exam without moving the patient around exhaustingly?

Your textbook offers a fantastic pro tip for choreographing your exam.

To save time and conserve the patient's energy, don't keep walking around them.

Have the patient sit up, stand behind them, and do the entire posterior exam first.

Inspect, palpate, percuss, and auscultate the back.

Then move to the front and repeat those same four steps for the anterior chest.

Let's walk through those steps, starting with inspection, which is simply looking at the patient.

We're taught to evaluate the AP to transverse diameter ratio.

Normally, a person's chest is wider across than it is deep.

Giving a ratio of about 0 .70 to 0 .75.

But sometimes you see a barrel chest where the ratio becomes equal to or greater than 0 .90.

Why does that happen?

A barrel chest happens in chronic conditions like emphysema or COPD.

The patient's lungs are chronically hyperinflated.

Over time, the body physically adapts to all that trapped air by pushing the ribs outward permanently.

The ribs become horizontal instead of sloping downward.

The patient's chest is essentially stuck in the inhale position.

That makes total sense when you picture the mechanics.

You also want to look at their posture.

A patient with COPD will often sit in what's called a tripod position, leaning forward with their arms braced on their knees or a table.

They do that to gain mechanical leverage.

Bracing their arms allows them to use their abdominal and neck muscles to help force the trapped air out of their lungs.

While you're observing this, you're also checking their skin and nails for cyanosis.

A bluish tint that signals tissue hypoxia, meaning the tissues are starved of oxygen.

You might also see clipping of the fingernails, a rounded bulbous distortion that happens from chronic long -term oxygen deprivation.

Step two is palpation feeling the chest.

We check for symmetric chest expansion by placing our warm hands on their back, pinching a small fold of skin between our thumbs at about the level of T9 or T10.

When the patient takes a deep breath, our thumbs should move apart evenly.

If there is a lag and one thumb barely moves, it tells you that something is physically preventing that specific lung from expanding.

That could be atelectasis, which is a collapsed section of the lung or heavy pneumonia consolidation, or even trauma like a fractured rib.

Next, we assess tactile fremitus.

I remember practicing this technique.

You use the ball of your hand or the ulnar edge, resting it on the patient's chest while they repeat the words 99.

The word 99 naturally generates strong palpable vibrations.

But what exactly are we feeling for and why?

This is all about the physics of sound conductivity.

Think about how you can hear a train coming from miles away if you put your ear directly to the solid steel train track, but you hear nothing through the air.

Solid objects conduct sound vibrations much better than air does.

Normal, healthy lung tissue is mostly air, so it doesn't conduct the vibration of 99 perfectly.

So if a patient has low bar pneumonia, where a section of the lung fills up with fluid and bacteria, that tissue becomes consolidated and solid.

Exactly.

Because that area is now solid, like the steel track, it conducts the vibration strongly to your hand.

You will feel increased tactile fremitus over a pneumonia.

On the flip side, decreased fremitus means there's a barrier blocking the vibration from reaching your hand at all.

That happens with the pneumothorax, where free air escapes into the pleural space between the lung and the chest wall, acting like sound insulation.

While our hands are on the patient, we also feel for crepitus.

How would you describe what crepitus feels like to a beginner?

Crepitus feels exactly like popping tiny bubble wrap under the spin.

It's a coarse crackling sensation.

It happens when air escapes the lung and gets trapped in the subcutaneous tissue, usually after trauma or a surgical procedure.

Moving to step three, percussion, or tapping the chest wall to hear the sound it produces.

When you tap over healthy, air -filled lung tissue, you hear a resonant sound.

It's low -pitched, clear, and hollow.

We contrast that normal resonance with two abnormal sounds.

First is hyperresonance, which is a lower -pitched, booning sound.

It tells you there's too much air present in that spot, like in a pneumothorax or emphysema.

Second is dullness, which is a soft, muffled thud.

Dullness signals an abnormal density, meaning something solid is taking up space where air should be like pneumonia, a pleural effusion, or a tumor.

But there is a limitation to percussion.

The tapping only sets the outer 5 to 7 centimeters of tissue into motion.

It cannot detect a deep lesion buried deep inside the lung.

That brings us to the final step of the physical exam auscultation, listening with a stethoscope.

The rules here are strict.

Use the flat diaphragm, listen to at least one full inspiration and expiration in each spot, and always compare side to side.

And you have to beware of background noise.

The rustling of a patient's gown or even your own breathing on the stethoscope tubing can mimic lung sounds.

When you listen to a healthy patient, you will hear three normal breath sounds depending on where you place your stethoscope.

Bronchial sounds are loud and high -pitched, heard right over the trachea in the neck.

Broncho -vesicular sounds have a moderate pitch and are heard centrally over the major bronchi.

And vesicular sounds are low and soft,

heard like a gentle rustling over the peripheral lung fields where air is flowing through the tiny bronchioles and alveoli.

But sometimes you hear atlanticious sounds.

These are added sounds that shouldn't be there.

The text lists several.

Crackles, which used to be called rails, are popping sounds usually heard when the patient inhales.

The book says it sounds just like rolling a strand of hair between your fingers right next to your ear.

Then there are wheezes or raunchy, which are musical squeaking or snoring sounds.

They happen when air is squeezed through airways that are narrowed by swelling or secretions.

We also need to highlight stridor.

Stridor is a high -pitched crowing sound heard during inspiration and is actually much louder up in the neck than in the chest.

Stridor is a massive red flag.

It indicates a life -threatening upper airway obstruction, like a child with severe croup or someone choking on a foreign body.

The text also mentions voice sounds, which we test if we suspect lung consolidation.

There's egophony, bronchophony, and whispered pectoriloquy.

These sound complicated, but how do they actually work?

They all rely on that same principle of solid tissue conducting sound better than air.

Take egophony, for example.

You ask the patient to say a long ee sound while you listen.

Normally, you just hear a muffled ee.

But if they have low bar pneumonia, the dense fluid changes the sound waves as they travel to your stethoscope.

That ee will actually distort and sound like a bleeding eye.

That's a positive egophony, and it strongly points to consolidation.

Now that we have all our clinical exams steps down, we look at objective measurements and developmental adaptations.

We use tools like the pulse oximeter, expecting a normal arterial oxygen saturation of 97 to 99 percent.

We might also use a spirometer to measure airflow.

With a spirometer, we look at the FeV1 to FeC ratio, the forced expiratory volume in one second compared to the total forced vital capacity.

Normally, that ratio is 75 percent or greater.

If it drops below 70 percent, it indicates obstructive lung disease.

Meaning the patient can get air into their lungs, but they physically cannot force it out quickly because the airways are blocked or collapsing.

We also have to adapt our physical exam based on the patient's age.

For infants, the text says to seize the opportunity.

If the baby is sleeping quietly in their parents' arms, completely ignore the usual head -to -toe sequence.

Listen to their lungs first before they wake up and start crying.

Though if they do cry, don't despair.

A baby crying actually acts like a natural amplifier, enhancing your palpation of tactile fremitus.

When assessing newborns, we use the APCAR score at one and five minutes after birth to measure their transition to life outside the womb.

The scoring looks at heart rate, respiratory effort, muscle tone, reflex irritability, and color.

A score of seven to ten at the one minute and five minute marks means the newborn is making a smooth transition.

The text notes some interesting anatomical differences in babies.

They are obligate nose breathers until they are about three months old.

They also rely heavily on their diaphragm to breathe, so seeing a baby's abdomen bulge outward with each breath is completely normal.

Their chest wall is also much thinner than an adult's.

Because they don't have thick layers of developed muscle or fat damping the internal sounds,

breath sounds will be much louder and harsher to your ear.

You'll typically hear bronchovesicular sounds throughout all the peripheral lung fields, which would be abnormal in an adult but is perfectly normal in an infant.

On the other end of the spectrum, when dealing with the aging adult or an acutely ill patient in the hospital, we have to modify our approach again.

Older adults tire out very quickly when we ask them to take deep breaths through their mouth for auscultation.

We have to give them breaks so they don't hyperventilate and get dizzy.

And if an acutely ill patient is bedridden and physically cannot sit up, you will need another nurse to help you roll them side to side.

You won't be able to get a perfect side to side comparison of the lungs in that position, but you still absolutely have to assess the uppermost lung.

Okay, this is the part where it all comes together.

Let's look at clinical applications.

How do all these isolated findings, inspection, palpation, percussion,

auscultation, combine to reveal a disease?

Let's treat these like mini case studies.

Let's start with low bar pneumonia.

If you walk into this patient's room, you will inspect an increased respiratory rate as they try to get enough oxygen.

When you percuss over the infected lobe, it won't be resonant.

It will be a dull thud because of the fluid.

When you listen, you'll hear loud bronchial breath sounds down in the periphery where they don't belong, along with crackles from the fluid.

And if you test voice sounds, egophony will be present.

What if the patient has asthma or COPD, specifically chronic bronchitis?

In that case, you will inspect a barrel chest and see them in the tripod position using their accessory neck muscles to heave air out.

When you auscultate, you will hear wheezing as air squeezes through narrowed pipes, and you'll notice their expiration phase is prolonged.

Overall, their breath sounds will be decreased because the air is trapped and just not moving efficiently.

Now imagine a pneumothorax, a collapsed lung caused by free air leaking into the pleural space.

The physical findings for a pneumothorax are dramatic.

On inspection, you'll see unequal chest expansion because one lung is totally deflated.

Palpation reveals completely absent tactile fremitus over the collapse.

You might even feel a tracheal shift where the pressure of the free air physically pushes the windpipe toward the unaffected side.

Percussion will be hyper resonant because you are tapping over a pocket of empty air.

And auscultation will reveal completely absent breath sounds over that lung.

Finally, the text discusses acute respiratory distress syndrome, or ARDS, and severe COVID -19.

These conditions cause diffuse alveolar damage.

The tiny grape -like walls are destroyed.

The patient will have acute dyspnea, extreme restlessness, and often frothy sputum.

Because the walls are damaged, no matter how much supplemental oxygen you give them, it cannot cross into the bloodstream.

This is called refractory hypoxemia.

You will hear widespread crackles and their blood work will show respiratory acidosis because the damaged alveoli can't exhale the carbon dioxide, allowing acid to build up in the blood.

Once we have assessed our patient, our final responsibility is safe practice and documentation.

If you assess a completely healthy patient, your charting needs to be clear and concise.

A perfect SOP note format starts with subjective data.

You would write no cough, shortness of breath, or chest pain with breathing.

For objective data, you summarize your exam.

AP diameter is less than transverse diameter.

Symmetric chest expansion.

Resonant to percussion.

Vesicular breath sounds clear bilaterally.

For your assessment, you conclude intact thoracic structures.

Charting accurately not only protects you as a nurse, but ensures the whole team knows exactly what the patient's baseline is.

Safe practice also means embracing our role as educators.

The text highlights health promotion, giving the specific example of a patient who smokes.

It is the nurse's job to educate them on the dangers of secondhand smoke.

Specifically explaining that it drastically increases the risk of recurrent ear and chest infections in children living in the home.

It's all about taking this deep textbook knowledge and applying it to protect the patient and their family.

That wraps up our journey through Chapter 19.

We've covered the anatomical landmarks, the nuanced interview questions, the step -by -step physical exam, the abnormal sounds, and how they all combine into clinical diagnoses.

Before we go, we want to leave you with a final, provocative thought based straight on the material we just covered.

Take a moment to consider how absolutely incredible it is that by simply using your bare hands, your ears, and your careful observation on the outside of the bony rib cage, you can accurately deduce the real -time microscopic condition of millions of invisible alveoli hidden deep inside the body.

That is the true power of mastering the physical exam.

You aren't just memorizing a textbook.

You are learning how to read the human body.

From the last -minute lecture team, thank you for studying with us today.

And the very best of luck on your upcoming exams and your future clinical shifts.