Anatomy Mini-Lesson – Popliteal Aneurysm!

Greetings Outlander anatomy students!

Much time has passed since my last post partly because I am nursing broken bones of my left ankle. I am working off an iPad, instead of my desktop computer, so it is slow going. đŸ˜±

Today’s lesson details Mr. Walter Woodcock’s dilemma as presented in Outlander episode 705, Singapore.

You will recall, Walter lies in the infirmary at Fort Ticonderoga with a significant injury to his right foot. The wound has turned gangrenous so an amputation is required.

Claire arrives to witness a medical dispute between Dr. Denzel Hunter and the pompous, Lieutenant Stactoe.

Curious Claire asks, what is going on? đŸ€”

Denzel recommends an above-knee amputation for Walter. Stactoe is adamant that a below-knee amputation makes for a more functional limb.

Stactoe is correct that in most circumstances, every attempt is made to salvage as much of a limb as is possible.

However, Denzel explains that Walter has a popliteal aneurysm, thus, an above-the-knee amputation is necessary! Claire palpates Walter’s calf and agrees with Denny.

Oh, oh! This changes everything! đŸ€”

There ensues a wee strammash when Stactoe says Claire will not use boiling water on HIS instruments. This is a direct quote from Diana’s An Echo in the Bone:

You will ruin the temper of the metal, subjecting it to boiling water!”

“No,” I said, keeping my own temper—for the moment. “Hot water will do nothing but clean it. And I will not use a dirty blade on this man.”

“Oh, won’t you?” Something like satisfaction glimmered in his eyes, and he clutched the blade protectively to his bosom.”

In the episode, Stactoe stomps off. But, no worries, Denzel to the rescue with his own set of fine surgical instruments!

To understand the implications of a popliteal artery aneurysm, let’s look at the anatomy of the arterial supply to the knee.

Essentially all of the lower limb is supplied by the huge femoral artery which begins at the groin and descends through the front of thigh. Near the top of the knee, the artery passes to the back of the knee and is renamed the popliteal artery (next figure). It then descends behind the knee joint. At the bottom of the joint, it splits into two and then into a third artery, all of which receive new names and supply lower leg and foot.

The hollow behind the knee joint is the popliteal fossa.

Try This:  Make a fist, bend opposite knee slightly, and tuck your fist into the hollow behind your knee. This is the popliteal fossa. Remove your fist and insert middle and ring fingers into the hollow. Press. You may be able to feel the pulsing of the popliteal artery in the popliteal fossa.

Feel it? Good job, students! đŸ€—

   
Next. The aneurysm! đŸ€“

A popliteal artery aneurysm, known by the acronym PAA, is a weak spot in the wall of the popliteal artery. Pressure exerted by arterial blood causes the weak spot to balloon into a palpable bulge behind the knee joint. This is of concern because if the aneurysm should burst, the blood loss would be difficult to control especially in an amputee.

Some causes of PAA are:

  • Atherosclerosis
  • High blood pressure
  • Wear and tear of the popliteal artery due to over use of knee joint
  • Weakening of the artery wall

The image show a couple different types of PAA.


Now, back to the episode!

Claire palpates Walter’s leg and agrees with Denzel. An above-knee amputation is best to avoid the aneurysm bursting with uncontrolled hemorrhaging.

A clear view of his damaged, gangrenous foot can be seen in the next image.

Unfortunately, Claire places her hands on either side of his calf. She cannot feel a PAA in this location because there is no popliteal artery behind the calf. Her hands should be up in the hollow of the knee.

Nevertheless, she gets an A+ for trying! đŸ€©

Also, in real life, the stench of gangrene would likely require them to mask and use some type of ointment under the nose to distract from the odor. 😼

And, today, imaging modalities would be used to determine the type and extent of a PAA.

In the final scene with Walter, Claire breaks the sad news that his condition does not permit him to be evacuated with the other patients.  He is to be left behind. 😱

Claire has a wonderful bedside manner which comes from her compassionate and caring heart. Hopefully,  the British will treat Walter well. đŸ€žđŸ»

Mercy! 😉

I hope you enjoyed today’s lesson. Just remember, if you ever feel a pulsing bulge behind  the knee, make an appointment swiftly or get into urgent care. A PAA is no joke!

The deeply grateful,

Outlander Anatomist

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Photo creds: Sony/Starz, www.myclevelandclinic.org, www.uptodate.com

Anatomy Lesson Outlander Trauma-Drama, Part 2

Hey, all.

Hope you had a grand couple of weeks awaiting part two of Outlander Trauma-Drama… Here it is. Yay!Â đŸ€—

Our last Anatomy Lesson, Outlander Trauma-Drama, Part 1, showed the system pathologists use to classify trauma. In that lesson, we covered different types of mechanical trauma including contusion, abrasion, laceration, incision, avulsion, projectile injury, and puncture wounds.

Remember? Yasss! 😊

    • Mechanical trauma
      • Contusion
      • Abrasion
      • Laceration
      • Incision
      • Avulsion
      • Projectile injuries
      • Puncture wounds
    • Thermal Injury
    • Radiation Injury
    • Personal Exposure (tobacco and alcohol)
    • Therapeutic Drugs
    • Air Pollution
    • Industrial Exposures
    • Agricultural Hazards
    • Natural Toxins
    • Oxygen Deprivation
    • Infectious Agents
    • Immunological Diseases
    • Genetic Derangements
    • Nutritional Diseases

Today’s lesson continues with the trauma-drama theme ‘cos there are still loads of Outlander owies to uncover and discover!

Again, examples from Diana’s big books and the Starz Outlander series will serve as anatomical models for the injuries. đŸ‘đŸ»

Today’s lesson will cover thermal injury and alcohol abuse. So, let’s get started!

There are six types of Thermal Injury:

    • Thermal burns
    • Hyperthermia
    • Chilblains
    • Hypothermia
    • Frostbite
    • Electrical injury

Here we go!

Thermal Burns: Thermal burns are caused by harmful exposure to heat, electricity, chemicals, or radiation.

Thermal burns are usually classified as first, second, or third degree burns. Occasionally, we hear of fourth degree burns, but do you ken there are also fifth and sixth degrees? Indeed there are! đŸ€“

Some students may have read Anatomy Lesson #5 and Anatomy Lesson #6 wherein we learned that skin is composed of epidermis (surface layer of skin cells) and dermis (underlying connective tissue). Thus, another useful way of grading thermal burns is to describe their relative depths.

Partial-thickness Burn: This type damages the epidermis or both the epidermis and outer dermis; it includes first and second degree burns. Such burns are red and may blister and are very painful. Most partial-thickness burns heal without scarring because hair follicle cells regenerate to cover the damaged surface. Even here, if a partial-thickness burn is too large, a skin graft may be required.

Full-thickness Burns: Full-thickness burns extend through both epidermis and  dermis and into underlying tissues. Such wounds are typically aesthetic (painless) because nerve endings are destroyed, although the rim of such a burn is usually painful. Full-thickness burns include third, fourth, fifth and sixth degree burns which may pass into muscle and bone. Fifth and Sixth degree burns are typically fatal.

We can imagine fifth and sixth degree burns suffered by poor Father Alexandre and Johiehon, his love interest in Outlander episode 412, Man of Worth.

Diana’s fourth big book, Drums of Autumn details the sad and horrific conflagration as the lovers burned to ash.

When the Indians had nearly finished with the priest, they untied him from the stake and fastened his hands instead to a long pole, held above his head, from which to suspend him in the flames….

… It was then that he had seen the Indian girl standing on Claire’s other side, with a cradleboard in her arms. … “She didna look to left or right, but walked straight into the fire.” … The flames had embraced the girl in moments. 

… “Her clothes caught, and then her hair. By the time she reached him, she was burning like a torch.” Still, he had seen the dark silhouette of her arms, raised to embrace the empty body of the priest. Within moments, it was no longer possible to distinguish man or woman; there was only the one figure, black amid the towering flames.

…The smell of burnt things hung in the air. We passed close by the pit and I couldn’t help seeing from the corner of my eye the heap of charred fragments, shattered ends frosted white with ash.

Hyperthermia: Hyperthermia  occurs if body temperature rises significantly above normal (>104 °F / 40 °C ). Many challenges, including infections, cause excessive body temperature.

Typhoid fever,  a.k.a. enteric fever, is caused by food and water contaminated with salmonella bacteria. Symptoms include:

    • High fever
    • Headache
    • Stomach pain
    • Constipation or diarrhea

A great example of hyperthermia appears in Outlander episode 310, Heaven and Earth. You remember Claire’s splendid  wee aide, Elias, who falls ill with typhoid? Claire is comforts him as he bravely succumbs to fever and dehydration. 😭

Cold temperatures đŸ„¶Â also cause thermal injury because the human body is poorly equipped to regulate and prevent heat loss; this is especially true of children and the elderly. Normally, fat deposits, heart, blood vessels, brain, skin, and muscles help combat cold. These organs provide insulation, induce shivering, re-direct blood flow from skin to vital organs, and reduce energy consumption.

However, exposure to cold temperatures over long periods of time overcomes our coping mechanisms and produces a range of thermal cold injuries such as chilblains, hypothermia, and frostbite.

Chilblains: Chilblains is a 16th century term for skin trauma due to repeated expose to cold, but not freezing, air. Digits are most commonly affected. The skin becomes red, swollen ,and itchy (next image), but usually heals without permanent damage.

Outlander TV episodes do not feature chilblains. But have no fear, our amazingly witty and resourceful Diana writes about it in her second book, Dragonfly in Amber, wherein Claire treats imprisoned men with chilblains.

She’s a wonder! Which “she” do I mean? Take your pick – either woman works!

I talked my way into the cells of the prison, and spent some time in treating the prisoners’ ailments, ranging from scurvy and the more generalized malnutrition common in winter, to chafing sores, chilblains, arthritis, and a variety of respiratory ailments.

Ouch, that looks a wee bit uncomfortable!

Hypothermia: Hypothermia occurs when the body’s core temperature drops below 95°F / 35°C as a result of extended cold exposure. Symptoms include low core temperature, vigorous shivering, confusion, sleepiness, slurred speech, shallow breathing, weak pulse, low blood pressure, changes in behavior, and slowed reactions.

Put simply, the victim of hypothermia experiences  the “umbles” meaning grumbles, mumbles, stumbles and fumbles because cold affects muscle and nerve response.

If the core temperature drops to 90Âș F / 32.2Âș C, then bradycardia (slow heart rate) and atrial fibrillation (fast and irregular contraction of the heart’s two upper chambers) may ensue.

The teenager, bad-lass Laoghaire, wasn’t suffering from hypothermia when she exposed her “ladies” to Jamie  in Outlander episode 109, The Reckoning, but she was well on her way!

Take a keek at that goose flesh! 😉

Frostbite: Frostbite is cold injury in which the body’s surface is exposed to freezing temperatures; it affects mostly feet, hands, noses, cheeks, and ears. And, as Prince Harry points out in his tell-all book, “Spare,” the todger must be protected from frostbite. This makes sense since it is also an appendage. 😉

Frostbite occurs in three stages:

    • Frostnip: Frostnip is a mild form of frostbite. Continued cold exposure leads to numbness in the affected area. As the skin warms, the sufferer feels pain and tingling but no permanent skin damage.
    • Superficial Frostbite: Superficial frostbite causes slight changes in skin color. The skin may begin to feel warm — a sign of serious skin damage. Rewarming at this stage causes the skin to appear mottled. The victim may notice stinging, burning and swelling. Fluid-filled blisters may appear over the next 12 to 36 hours (next image).
    • Deep Frostbite. As frostbite progresses, it affects all layers of the skin and underlying tissues. The skin turns white or blue-gray; all sensation of cold, pain, or discomfort is lost in the affected area. Joints or muscles may stop working. Large blisters form 24 to 48 hours after rewarming. The tissue turns black and hardens as it dies. Amputation is usually warranted.

Claire teasingly relates how she and Jamie avoid getting frostbite in this steamy tidbit from Drums of Autumn.

His mouth was warm and soft, and whether he approved of what he was doing or not, he did it awfully well.

…“Ooooh,” I said, and shuddered ecstatically as his teeth sank delicately into my earlobe.

….“Oh, well, if it’s like that,” he said in resignation, and taking my hand, pressed it firmly between his thighs.

..“Gracious,” I said. “And here I thought the cold 
”

…“It’ll be warm enough soon,” he assured me. “Get them off, aye?”

…It was rather awkward, given the cramped quarters, the difficulty of staying covered in order not to suffer frostbite in any exposed portions, and the fact that Jamie was able to lend only the most basic assistance, but we managed quite satisfactorily nonetheless. 😅

Electrical Injury: What is this? Electrical injury is damage to the skin or internal organs after a person comes into direct contact with a high-voltage source. An electric shock can be life-threatening.

Good advice: Get emergency help if the source of the injury is a high-voltage wire or lightning. Even those with minor injuries or no symptoms should be checked by a physician for internal injuries because these may not be evident to the non-professional.

Rare but life-threatening symptoms include severe burns, muscle pain and contractions, seizures, and unconsciousness. In some cases, heartbeat and breathing may be difficult to detect.

In the US, there are approximately 1000 deaths per year, as a result of electrical injuries. Of these, approximately 400 are high-voltage electrical injuries and lightning causes 50 to 300. There are also at least 30,000 shock incidents per year that are non-fatal.

If you think these stats are grim, consider the UK: Faulty electrical equipment and sockets cause approximately 70 deaths and 350,000 injuries in UK homes every year (RHA, 2022). Such figures show how important it is to follow electrical safety guidelines.

Outlander book and TV don’t really contain much about electrical injury. the closest I can come is Claire’s eerie encounter with Otter-Tooth’s ghost in Outlander episode 403, The False Bride. Here, she experiences the aftermath of a lightning strike.

Diana describes the scene in vivid detail. Again, from Drums of Autumn:

Sheet lightning shimmered far away, across the mountains. Then more bolts, sizzling across the sky, each succeeded by a louder roll of thunder. The hailstorm passed, and the rain resumed, pelting down as hard as ever. The valley below disappeared in cloud and mist, but the lightning lit the stark mountain ridges like bones on an X ray.

I woke all the way to the smell of burning, and sat bolt upright. The rain had stopped; it was the silence that wakened me, I thought. The smell of smoke was still strong in my nostrils…

…The ground rose in front of me to a small ridge. At the top of this stood a large balsam poplar tree, the source of the smoke. The tree had been struck by lightning; half of it still bore green leaves, the canopy bushy against the pale sky. The other half was blackened and charred all down one side of the massive trunk. Wisps of white smoke rose from it like ghosts escaping an enchanter’s bondage, and red lines of fire showed fleetingly, glowing beneath the blackened shell.

Echoes of the shock of impact wavered through my flesh, and I tried frantically to fit myself back into my body. Then I drew breath, a painful gasp, and found myself shaking, the shock turning to the first intimations of damage. I lay still, eyes closed, concentrating on breathing, conducting an inventory. 

…The rain was still pounding down onto my face, puddling in my eye sockets and running down into my ears. My face and hands were numb. My arms moved. I could breathe a little easier now.

Drenched in cold, relentless rain, Claire spies the spooky ghost of Otter-tooth. Careful, lest you get hyperthermic, Claire!

And, there he is. Sharp as an Otter’s Tooth!

That is it for thermal injury. But….

Here’s some exciting thermal news: The US Department of Energy is developing clothes with thermal properties that adapt to the environment and to the wearer’s body. By changing the make-up or shuttling heat to and from the body, the garments can keep people comfortable whatever the external temperature (30 January 2016, New Scientist). I’m ready for one of these jackets, how about you?

Onward! 

Alcohol: Alcohol is a colorless, volatile, and flammable liquid that is the intoxicating element of wine, beer, and other spirits (duh!); it is also used as a fuel and is an industrial solvent! 😼

How the body handles alcohol: The stomach lining contains alcohol dehydrogenase (ADH), an enzyme which metabolizes alcohol. The liver also has ADH plus other enzymes that help break down alcohol. But, bad news for the lassies: Women naturally have lower levels of GAD than men and often develop higher blood alcohol levels after drinking the same or even less alcohol. So, be wary if ye are an XX!

Claire offers a pithy analysis of alcohol in this quote from the big book, “Drums of Autumn,“wherein Jamie gets John Quincy Myers drunk in preparation for his hernia surgery.  (Psst…Non-book readers ken Claire performed this surgery on Edmond Fanning in episode 408, Wilmington.)

“Alcohol isn’t a good anesthetic at all,” I said, shaking my head. “It’s a poison. It depresses the central nervous system. Put the shock of operating on top of alcohol intoxication, and it could kill him, easily.”

And, there we have it in a nutshell!

Not surprisingly, alcohol is the most widely used and abused toxic agent in the world. (Not meaning to preach as I enjoy a wee bit now and then)

Alcohol injury ranges from binge drinking to full on alcoholism with a myriad of accompanying ailments. Most of us are well-versed on the effects of excessive alcohol intake and realize some effects are acute and others are chronic.

Acute Alcohol Intoxication: In the US, there are over 3,000,000 reported cases of acute alcohol intoxication (AAI) from drinking too much, too quickly. Symptoms include slurred speech, incoordination, mood and behavioral changes, and poor judgement. Acute alcohol intake effects breathing, heart rate, body temperature, gag reflex, and can lead to coma and death. (psst… I wager many more cases go unreported) đŸ«ą

Risk factors include:

      • Injuries, such as motor vehicle crashes, falls, drownings, and burns.
      • Violence, including homicide, suicide, sexual assault, and intimate partner violence.
      • Alcohol poisoning, a medical emergency that results from high blood alcohol levels.
      • Risky sexual behaviors, including unprotected sex or sex with multiple partners. These behaviors can result in unintended pregnancy or sexually transmitted diseases, including HIV.
      • Miscarriage and stillbirth or fetal alcohol spectrum disorders (FASDs) among pregnant women.
Alcohol intoxication is managed with rest, hydration, and abstaining from alcohol. It is worth noting that severe cases may require hospitalization, intravenous fluids, observation, and supportive care.

Oh, Jamie is in the throes of AAI at Lallybroch (episode 112, Lallybroch). He is stinking drunk as he stumbles into the bedchamber reeking of booze; Claire is not “amoozed.” 

But, he looks marvelous in his da’s splendid leather coat! 😜 

Chronic Alcohol Use: Alcohol Dependence Syndrome (ADS or alcoholism) is a condition characterized by long-term alcohol dependence and alcohol abuse that result in specific physiological and behavioral problems. ADS  includes ten or more different signs and symptoms, but from a medical standpoint, only two are required for diagnosis. Chronic use causes a host of problems, including:
    • High blood pressure, heart disease, stroke, liver disease, and digestive problems.
    • Cancer of the breast, mouth, throat, esophagus, larynx, liver, colon, and rectum.
    • Weakening of the immune system, increasing the chances of illness.
    • Learning and memory problems, including dementia and poor school performance.
    • Mental health problems, including anxiety and depression.
    • Social problems, including family problems, job-related problems, and unemployment.
    • Alcohol use disorders, or alcohol dependence

In season six of Outlander, we witness Fergus falling into ADS as he struggles with the cruelty and intolerance toward his dwarf son (episode 603, Temperance).  Alcohol  is commonly used to cope with personal tragedy and trauma.

You remember Colum MacKenzie back in Outlander, seasons 1 and 2?  Yes, of course ye do! 😊 Claire diagnosed Colum as a sufferer of  Toulouse-Lautrec Syndrome, also known as pycnodysostosis. 

Colum required large quantities of rhenish wine (9% alcohol content) to quell and dispel the agony of his existence (Outlander episode 102, Castle Leoch). 

…  “I beg your pardon?” I turned, having missed Colum’s words in the growing noise, to find him offering me the decanter, a lovely bell-shaped thing of pale green crystal.

The liquid within, seen through the glass, seemed green as the sea-depths, but once poured out it proved to be a beautiful pale-rose color, with the most delicious bouquet. The taste was fully up to the promise, and I closed my eyes in bliss, letting the wine fumes tickle the back of my palate before reluctantly allowing each sip of nectar to trickle down my throat.

“Good, isn’t it?” The deep voice held a note of amusement, and I opened my eyes to find Colum smiling at me in approval. I opened my mouth to reply, and found that the smooth delicacy of the taste was deceptive; the wine was strong enough to cause a mild paralysis of the vocal cords.

“Won—wonderful,” I managed to get out. Colum nodded.

“Aye, that it is. Rhenish, ye know. …”

Clearly, Colum suffered from his genetic disability but also from ADS . Near the end, when rhenish no long offered the needed relief, he turned to Claire to assist him in end of life options (Outlander episode 210 Prestonpans).

ADS is considered a medical emergency because it can lead to coma and death. Guidelines exist about the amount of alcohol the liver can metabolize per hour and these rates should not be exceeded. Again, please get informed if this is an issue in your life.

As a final example, we see wee Flora MacDonald taking a wee nip from her personal hip flask in Outlander, episode 605, Give Me Liberty!  Now, just because she carries a personal flask, it doesn’t mean she is suffering from either acute or chronic alcohol poisoning! 😉

Finally, this is an interesting tidbit. Some people carry a gene variant encoded for alcohol dehydrogenase (ALDH2*2) that stops the enzyme working, so these folks experience flushing soon after drinking. This happens because they have a lowered ability to metabolize alcohol and includes some 8% of the world’s population. Now, a link has been found showing that this gene raises heart disease risk in those who experience alcohol flush (New Scientist, 4 Feb. 2023). The risk of heart disease is four times greater in regular drinkers with the defective gene! if you flush immediately after alcohol ingestion, you may wish to consult your physician?

OK, that is our lesson for today. But before we call it quits let’s have a –

Pop Quiz! 

Name the injury (red arrow) Jamie sports after the Battle of Alamance, in Outlander episode 507, The Ballad of Roger Mac.

What was that you said?

An abrasion? Â đŸš«

A laceration? đŸš«đŸš«

An avulsion? đŸš«đŸš«đŸš«

What was that you said?

 

 

A contusion? Yep!

Well done, anatomy students! đŸ‘đŸ»đŸ‘đŸ»đŸ‘đŸ»

Next time, Part 3!

The deeply grateful,

Outlander Anatomist

Follow me on:

Photo creds: Sony/Starz, www.en.wikipedia, www.britannica.com

 

Mini Anatomy Lesson: Claire’s Beating Heart

 

Greetings all anatomy students. There has been a dry spell of lessons this summer while I attended to blueberry crops and fruit trees! Berries are now done for the year and time to return to Outlander. Yay!

So, let’s get right to it.

During Episode 606, The World Turned Upside Down, Claire becomes deathly ill, not from what ails the MacNiel family, but from Malva Christie poisoning! 😈 😳

During an intense fever dream, Claire has a vision of roiling clouds and an amoeba. But then, her hands cradle something red and pulsing –  her beating heart in this startling and somewhat gruesome image: 

Fortunately, the show’s FX provides me with a splendid opportunity to teach students about the heart, a complex and essential organ. Oh, goodie! 😜

Learn: So, let’s study the heart!

This Mini Lesson will cover heart size, shape, position, apex, base, chambers, valves, cardiac muscle, and blood flow.  Because the heart is fairly complex, I will try to keep the explanations as compact and useful as possible. đŸ€“

Size: First, how big is the human heart? The human heart is roughly the size of the person’s closed fist. âœŠđŸ»Â Thus, a man’s heart is usually slightly larger than a woman’s and both are larger than a child’s. 

Try This: Make a fist and take a keek at it. It is likely close to the size of your own heart. If you are female, ask a male family member or friend to make a fist and explain what it means. Ditto for a child in your life.

Fun Fact #1:  We sometimes compliment a generous person saying they having a “big heart.” But this is just a figure of speech. One doesn’t really want a big heart because a smaller heart is usually a healthier heart.  Interestingly, people who exercise regularly tend to have smaller hearts that beat more efficiently. However, recent studies show some premier athletes who vigorously engage in prolonged exercise may have a slight enlargement of the heart muscle, but this is a somewhat unique situation.

Shape: What shape is the heart? I think it is worth while to point out that the heart is not shaped like a Valentine! 😉 Overall, its shape is so complex it is a bit challenging to explain. But, let me give it a try.

Alrighty then. If the heart is NOT shaped like a Valentine, what is its shape? Turns out, the heart is shaped something like a squat, plump hand iron without a handle! Yep. đŸ‘đŸ»

Here it is from a frontal view.  The heart is outlined in black. It is a bit difficult to visualize because the heart is somewhat obscured by the many vessels leading to and from it.  (The right view shows the heart from behind)

Position: Now, exactly where does the heart reside in the body? It sits in the chest nestled between right and left lungs and just above the respiratory diaphragm (black line in next figure).

About 2/3 the heart lies behind the sternum (breast bone) and about 1/3 projects to the left of the sternum with a wee bit to the right.

The heart does have a point but it is not directed downward as seen in Episode 606 (and many other films), but toward a person’s left side – bear in mind the hand iron image! 

Apex: The point of the heart is its apex. The apex lies at the 5th intercostal space (between the 5th and 6th ribs), a little below the nipple (but, only if the breast is high). It is nearer the rib cage than the rest of the heart making the 5th intercostal space an important landmark for hearing the heart beat.

Base: The heart has a base but it is not the surface nearest the diaphragm, as one might expect.  Rather, the base is opposite the apex and lies nearer the right lung. 

 

Next is a closer view of the heart nestled between left and right lungs (shown in pale pink). The black arrow marks the apex of the heart and the red arrow marks its base.  Notice there is a distinct notch in the left lung to accommodate the apex; this is the cardiac notch. Again, the respiratory diaphragm is not shown in the image, but it lies directly under the heart.  

Chambers:  The human heart is divided into four chambers, each designed to receive blood. Two smaller chambers that form the base are the atria (pleural of atrium). The ventricles are two larger chambers that form the apex and sides of the heart. These chambers are named: right (R) and left (L) atria and R and L ventricles; each plays a unique role.

In the cut-away view below, we see all four chambers. Notice these are on opposite sides than the viewer’s heart because the image is designed for a health care practitioner viewing the heart of a patient. đŸ€’

In digital images, the chambers are usually color-coded. R atrium and R ventricle are blue whereas L atrium and L ventricle are red. This color designation indicates oxygen levels of the blood in each chamber. 

Bottom Line: The R two chambers are blue meaning they contain oxygen-poor blood that has just returned from the body (head, limbs, trunk). The L two chambers are red indicating they contain oxygen-rich blood that has just returned from right and left lungs.

Valves: The heart is also equipped with four valves which control the flow of blood passing through the chambers. If a valve is open, the blood flows through it. If a valve is closed, then blood cannot back flow. đŸš«

The four valves are (next image):

    • Tricuspid Valve: This valve has three flaps and lies between R atrium and R ventricle. 
    • Mitral (Bicuspid) Valve: This valve has two flaps and lies between L atrium and L ventricle.
    • Pulmonary Valve: This valve has three pockets and lies between R ventricle and pulmonary artery (leading to the lungs).
    • Aortic Valve: This valve has three pockets and lies between left ventricle and aorta (carries blood to the head, limbs and trunk).

Cardiac Muscle: Just a note about heart (cardiac) muscle. Cardiac muscle is a special tissue only found in the heart. It has the ability to contract. It is thicker in the ventricles and thinner in the atria because the ventricles work harder to pump blood through the lungs and the body. The atria have thinner walls because their lighter workload consists of moving blood into their respective ventricles. Impulses from specialized cells stimulate cardiac muscle to rhythmically contract. We call this cycle of contraction and relaxation, the heart beat or cardic cycle.

 

OK, this ends the basic anatomy (although, there is much more). So let’s look as how the heart works.

Blood Flow: The heart is a pump. Similar to a pump that pushes water through a hose, the heart contracts rhythmically to pump blood through our vessels. As long as the heart continues to pump, blood continues to flow, delivering life-giving oxygen and nutrients to tissues and cells and removing carbon dioxide and waste products. 

Our hearts only work if our vessels form a continuous loop. If a vessel is cut or disrupted, then blood seeps through the opening; if blood loss is significant, then pressure falls and the heart can no longer pump normally. This explains why injury of a major vessel must be cared for ASAP.

FUN FACT #2: The human body contains some 60,000 miles of blood vessels – enough to encircle the earth 2.5 times! The heart works hard to pump blood through this vast network. 

FUN FACT #3: Each day the average heart beats 100,000+ times and pumps about 2,000 gallons of blood. In a 70-year lifetime, an average human heart beats more than 2.5 billion times! Super star! đŸ€©

How it Works: The heart is designed to receive blood via its atria and deliver blood via its ventricles (see image below). There really isn’t a simple way to describe this complex process but let’s give it a go! đŸ‘đŸ»

    • R Atrium: Oxygen-poor blood from the body is delivered to the  R atrium via two large vessels (superior and inferior vena cavae). The R atrium contracts, the tricuspid valve opens, and blood pours from R atrium into R ventricle.
    • R Ventricle: The R ventricle contracts, the tricuspid valve closes, and blood exits through the pulmonary valve into the pulmonary artery whose branches deliver blood to R and L lungs (where it rids itself of carbon dioxide and picks up oxygen).
    • L Atrium: Oxygen-rich blood from the lungs is delivered to the left atrium by pulmonary veins. The L atrium contracts, the mitral valve opens, and blood pours from L atrium into L ventricle.
    • L Ventricle: The L ventricle contracts, the mitral valve closes, and blood exits through the aortic valve into the aorta whose branches deliver oxygen-rich blood to the body.

Cardiac Cycle: Now that you know what each side of the heart does, let’s see how the sides work together. Keeping in mind what each chamber does, understand that both atria contract simultaneously followed by both ventricles. The span of one heart beat to the next is the cardiac cycle.

Lub-Dub: The heart beat is described in anatomy and medicine as a lub-dub sound. Lub-dub sounds are close together followed by a brief pause. These sounds are caused by blood striking closed valve flaps.

    • Lub sound is caused by blood striking tricuspid and mitral valves as they close, simultaneously.
    • Dub sound is created by blood striking pulmonary and aortic valves as they close,  simultaneously.

This video offers a good representation of the cardiac cycle. Watch for the contraction of atria and ventricles and then the pause.  Also, watch valve flaps open and close as the heart chambers contract. In this animated film, only the cardiac vessels, which bring blood to and remove blood from the heart, are color-coded blue and red.

 https://youtu.be/ebzbKa32kuk

Try This: If you have a stethoscope, place it under the left fifth rib, in line with the nipple and listen for the lub-dub sounds. If you don’t have this tool, ask a partner or your child to lay down and place your ear in the same spot and try to hear the sounds of the valves closing. This is a totally awesome experience, especially if you know what it means! 

This animated video helps us to further understand the cardiac cycle –  you know the trope, “a picture is worth a thousand words.”

Fun Fact #4:  I suspect you all know that heart disease is the leading cause of death in men AND women, worldwide. But, recently it has been found that some Old Order Amish people have a rare genetic mutation which reduces the risk of heart disease by 35%! The gene has been duplicated in mice. Efforts are now underway to produce a drug that may reduce heart disease in the same way as the gene mutation. Let’s hope it works! đŸ€žđŸ»

I hope now you have a better understanding of and appreciation for your own heart. We sort of take it for granted that hearts will always be there working for us. But, the heart is susceptible to disease and is not an easy organ to understand. Its embryology is even more complex which accounts for the frequency of cardiac birth defects. You did well, though. Keep up the good work! 

Whew!  😅

Read about Claire’s beating heart in Diana’s sixth big book, “A Breath of Snow and Ashes.” This passage vividly describes her wild fever dreams as her body battles the infection planted by Malva. In Claire’s dream, her heart is the main character!

I seldom knew whether my eyes were open or closed, nor whether I woke or slept. I saw nothing but a roiling gray, turbulent and shot with red. The redness pulsed in veins and patches, shrouded in the cloud. I seized upon one crimson vein and followed its path, clinging to the track of its sullen glow amid the buffeting of thunder. The thunder grew louder as I penetrated deeper and deeper into the murk that boiled around me, becoming hideously regular, like the beating of a kettledrum, so that my ears rang with it, and I felt myself a hollow skin, tight-stretched, vibrating with each crash of sound. 

The source of it was now before me, throbbing so loudly that I felt I must shout, only to hear some other sound—but though I felt my lips draw back and my throat swell with effort, I heard nothing but the pounding. In desperation, I thrust my hands—if they were my hands—through the misty gray and seized some warm, moist object, very slippery, that throbbed, convulsing in my hands. 

I looked down and knew it all at once to be my own heart. 

I dropped it in horror, and it crawled away in a trail of reddish slime, shuddering with effort, the valves all opening and closing like the mouths of suffocating fish, each popping open with a hollow click, closing again with a small, meaty thud. đŸ€Ż

See Claire’s beating heart in Outlander Episode 606, “The World Turned Upside Down.”

Let’s all hope our hearts continue to serve us as long as possible. From my heart to yours! ♄

The deeply grateful,

Outlander Anatomist

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Photo and Video Credits: Starz, Sony, Outlander Anatomy, www.arcreativemedia.com,  www.bemfi.fi, www.commons.wikimedia.org, www.covenanthealth.com, www.en.wikipedia.org, garmentsteamerguide.com, www.heart.org, www.heartsearch.org.uk, www.Luxsontube.com, www.medlineplus.gov, www.slideplayer.com Â