Anatomy Lesson #42: “The Voice – No, not that One!”

Welcome anatomy students to another exciting session! Today’s Anatomy Lesson #42 is, The Larynx. Some folks think the larynx only generates “The Voice” (Christina, CeeLo, Blake and Adam, notwithstanding). While this is certainly true, it also serves two other critical functions. Stay tuned for the fascinating saga of laryngeal (adj.) anatomy.

As always, Starz images and Diana’s book quotes are sprinkled throughout to make our studies more endearing. A couple of book spoilers appear, meaning the quotes are from books that have not yet been filmed; these will be preceded by a red flag warning for those who prefer to skip!

First, the sad-bad news. I waited for Starz to depict Dougal’s Demise after a reader asked more than a year ago for a lesson on the voice! I waited patiently because Uncle D’s Death as described in Dragonfly in Amber book is a perfect lead-in for a larynx lesson. Then, horror of all horrors – Starz episode 213, Dragonfly in Amber – didn’t follow the book! Och!

BOOK QUOTE: Dragonfly in Amber describes Jamie’s and Dougal’s shocking Fight with Fate, involving a knife to the throat and a struggle with voice:

A shift, and a jerk, a sudden grunt of effort, one of pain. Dougal stepped back, staggering, face congested and pouring sweat, the hilt of the dagger socketed at the base of his throat… There was a terrible sound from Dougal, a sound of shock and stifled breath… The big body went limp, then spasmed, sliding out of Jamie’s grasp. Dougal lay crumpled on the floor, muscles jerking with involuntary contractions, struggling like a fish out of water. His head was pillowed on Jamie’s thigh. One heave brought his face into view. It was contorted, and dark red, eyes gone to slits. His mouth moved continuously, saying something, talking with great force—but without sound, save the bubbling rasp from his ruined throat.

Imagine my dismay as the Starz scene unfolds wherein Jamie + Claire stab Dougal in the chest – not in the neck!  What? To quote Rabbie Burns: “The best laid schemes o’ mice an’ men – gang aft a-gley.” Ah, well, tha sin mar sin!

ep 213 Dougal 01

Many a time, Jamie casts a wary eye at Dougal (Starz episode 101, Sassenach) and for good reason. Mayhap, the ruadh laddie kens that a battle to the death is the only way a male will prevail? One of these fellows must go!

ep 101 larynx

Now for the lesson: Let’s start at the beginning with how to pronounce the word, larynx.  Well, it is pronounced ler-inks, not lar-nix. Emma does a swell job, so check this out:

https://www.youtube.com/watch?v=4mX4-zer2e0

Commonly known as the voice box, the larynx is a splendid structure of startling complexity. A hollow tube with stiff walls, the adult larynx (Image A – orange) lies in the neck where it links pharynx or back of throat (Image A – green) with trachea or windpipe (Image A – trachea).

Just so you are aware, pharynx is pronounced fare-inks, not far-nix. One of my anatomy profs used to declare: “if you say lar-nix one more time, I will rip out your far-nix” (in those days, professors were minor gods)!

The human larynx serves three critical functions:

  • Maintains the airway so air enters and leaves the lungs during each breath cycle
  • Excludes food, drink and other unwanted stuff from entering trachea
  • Creates phonation – “the voice” and other sounds

We will learn how the larynx manages these important functions. But first, the anatomy!

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Image A

General Anatomy of Larynx:

A vertical, midline section through the larynx reveals its considerable length, extending from C3 (third cervical) vertebra (Image B – red arrow) through C6 vertebra (Image B – blue arrow). In case you forgot, back in February 2015, we learned about cervical vertebrae in Anatomy Lesson #12, “Claire’s Neck” or “The Ivory Tower.”

The adult larynx is supported by a rigid skeleton of cartilage, ligaments and membranes (Image B – cartilages named). Numerous intrinsic and extrinsic muscles move these cartilages.

Its hollow interior is lined with mucous membrane or wet mucosa (Anatomy Lesson #14 ,“Jamie and Claire” or “Anatomy of a Kiss”), meaning the surface is moist, a necessity because its living cells will die if allowed to desiccate.

The larynx is a dynamic structure that changes throughout life, from the newborn state through old age. It is also a secondary sex organ undergoing marked changes during puberty. Male and female larynges (pl.) respond differently to the internal hormonal milieu, a quality known as sexual dimorphism (Anatomy Lesson #39 “Dem Bones – the Human Skeleton”). We will return to these issues later in this lesson.

larynx-01-Figure0059

Image B

Laryngeal Skeleton:

The laryngeal (adj.) skeleton features nine cartilages: three large, unpaired and three small, paired. Only unpaired cartilages (epiglottis, thyroid and cricoid) are visible from a front (anterior) view (Image C). The rounded, curved tip of epiglottis peeks above the hyoid bone. The thyroid cartilage is shaped like a helmet visor; two broad plates (laminae) meet anteriorly at a pronounced angle, the laryngeal prominence (Image C – red arrow). The cricoid cartilage is a complete ring, thin in front but expanded in back.

larynx-02-Figure0073A

Image C

Laryngeal cartilages do not float, they are anchored by strong connective tissue elements (Image D). The thyroid cartilage hangs from the hyoid bone (Anatomy Lesson #12, “Claire’s Neck” or “The Ivory Tower”) via a tough thyrohyoid membrane. Cricoid and thyroid cartilages are united by the cricothyroid ligament and a cricotracheal ligament (Image D – red arrow) binds cricoid cartilage to trachea. Although not shown in Image D, ligaments also hold the epiglottis in a mostly vertical position. The trachea is not part of the larynx but its wall is also formed of cartilage rings (see below).

larynx-05-Figure0073A

Image D

WARNING! The first RED FLAG means a book spoiler quote is next! Skip, if need be.

redFlag

BOOK SPOILER: Larynx and hyoid bone appear in Diana’s 9th book, Written in My Own Heart’s Blood. An important character’s name is omitted to “protect the innocent!”

McEwan’s broad fingers were cold on his neck; he felt the icy touch delicate on his skin as it traced the line of the rope scar, then firmer as the healer prodded gently round his damaged larynx… McEwan fitted his hand snugly round _______ neck, just under the chin… “Do you know what a hyoid bone is?” “If I had to guess, it’s something in the throat.” “Why?” … “It’s just there,” the healer said, pressing with his thumb, high up under _______ chin. “And if it had been here”—he moved the thumb down an inch—“ you’d have been dead, sir. It’s a fragile wee bone. Easy to strangle someone by breaking it—with your thumbs or a rope.”

Question #1: Do any of the above structures appear as mounds at the skin surface? Hyoid bone, epiglottis and cricoid cartilages are not visible because these are embedded too deeply or are too small to create a skin mound. But, we often see a bulge that moves during swallowing, talking, singing, etc.; the bulge is created by the laryngeal prominence of the thyroid cartilage, commonly known as the Adam’s apple (Image E). Great tattoo, although most of it lies below the laryngeal prominence. Ha!

Try This: Place two fingers over your laryngeal prominence – don’t press hard as it causes discomfort. If you cannot find it, gently tilt head backwards and feel a firm mound under your fingers. Now, straighten the neck and feel the prominence lift as you prepare to swallow and fall as the act completes. Now cough or sing a few bars and see what happens. I hope you are surprised by its mobility. Remember, this is only a small part of the larynx; much more is happening that you cannot feel.

Try This: Next, tilt head back again and run fingers down the laryngeal prominence until you feel soft tissue; this is the cricothyroid ligament. Below it lies a thin hard line of cricoid cartilage. Below this is another bit of soft tissue, the cricotracheal ligament binding cricoid cartilage to first tracheal ring. From this point, the trachea continues down the throat and into the thorax (Anatomy Lesson #15 “Crouching Grants – Hidden Dagger”). Appreciate that the larynx is solidly built and well-anchored.

Clinical Correlation: If an “owner” desires a smaller laryngeal prominence, then chondrolaryngoplasty is available. The neck is entered via surgical incision and the prominence reduced by shaving. Erroneously called a tracheal shave (trachea isn’t involved), it usually leaves a modest scar.

Adam's apple

Image E

Time for a Jamie fix! Jamie’s laryngeal prominence is clearly visible (Starz episode 210, Prestonpans – red arrow) as, tilting his head back with immense pleasure, he relieves a full bladder! Hot-shot lad that he is, he attempts to win a bet by peeing into a pot without looking. Splish-splash! Odds?

BOOK QUOTE: Diana describes the delightful scene featuring Jamie’s Adam’s apple (Dragonfly in Amber):

Grinning at the success of his joke, he raised his kilt further, grasped his clearly visible weapon and took careful aim. He squinted his eyes, bent his knees slightly, and his fingers tightened their grip. Nothing happened. “It’s a misfire!” crowed one of the English. “His powder’s wet!… Jamie squinted dubiously at his equipment, bringing on a fresh riot of howls and catcalls. Then his face cleared. “Ha! My chamber’s empty, that’s all!” He snaked an arm toward the array of bottles on the wall, cocked an eyebrow at me, and when I nodded, took one down and upended it over his open mouth. The water splashed over his chin and onto his shirt, and his Adam’s apple bobbed theatrically as he drank. “Ahhh.”

ep-210-adams-apple

Back to Anatomy: The best way to see remaining laryngeal cartilages is flip the structure into a posterior view (Image F). The odd, leaf-like epiglottis is fully visible from this perspective; it’s curved superior surface peeking above the hyoid bone. Thyroid cartilage, visor-shaped, is incomplete, posteriorly. The cricoid cartilage expands in back, much like the dome of a signet (class) ring. Perched atop the cricoid are the important, paired arytenoid cartilages, each shaped like a three-sided pyramid. Atop each arytenoid is another small curved cartilage (corniculate) which we will ignore along with a couple of other tiny cartilages. Although difficult to visualize from this perspective, a lumen (channel) runs vertically through the center of the laryngeal cartilages; remember, this lumen is lined with mucous membrane.

Posteriorly, the tracheal rings are incomplete, but the C-shaped cartilages are united by strong connective tissue sheets. This brilliant engineering feat allows food blobs and globs to slide and glide down the esophagus (see Image B – esophagus behind trachea) without getting hung up on tracheal rings.

larynx 03 Figure0073B

Image F

One last structural component to consider are the paired vocal ligaments. A vertical section of the larynx, through the midline, reveals internal anatomy of the left side of larynx (Image G). Locate the left vocal ligament, a band of elastic tissue reaching from thyroid cartilage in front to arytenoid cartilage, in back. This arrangement is duplicated on the right side. More about the vocal ligaments below.

larynx 04 Figure0073E

Image G

Intrinsic Laryngeal Muscles: Intrinsic muscles arise and insert within the larynx itself. There are 6 (8 by some counts) pairs of intrinsics; thin, tiny muscles moving various laryngeal cartilages. I can bear witness that these are very difficult to dissect! One of a pair of intrinsic muscles is clearly visible from a side view (Image H – red arrows). Naming intrinsic muscles will bog us down. Suffice it to say, the one in Image H is the cricothyroid, so named because it arises from cricoid cartilage and inserts on thyroid cartilage. Get the idea? Grand!

Muscles-02-Figure0074B

Image H

Remaining intrinsic muscles are visible from a posterior view (Image I). These are strategically oriented to move the various laryngeal cartilages in specific ways and again, named by the cartilages they attach to or the function they perform.

Muscles 01 Figure0074A

Image I

The following is a short list of how intrinsic muscles act on various laryngeal cartilages.

  • Rock thyroid cartilage forward to lengthen vocal ligaments and deepen the voice (Image J – top)
  • Rotate arytenoid cartilages together to open airway and allow airflow (Image J – middle, left)
  • Rotate arytenoid cartilages apart to close airway and stop airflow (Image J – middle, right)
  • Narrow the airway to reduce airflow (Image J – lower, left)
  • Tense vocal cords to raise voice pitch (Image J – lower, right)

Ergo, these intricate adjustments, caused by muscle contraction, allow nuanced movements of laryngeal cartilages to manage airflow and to produce and modulate sound. And, these amazing, small muscles contract very rapidly with great capacity for prolonged work, as any singer can verify. Lastly, the lower right image shows muscle fibers stretched from thyroid to arytenoid cartilages; these tiny muscles lie inside the vocal folds (see below).

Muscles 05 larynxFigure0075

Image J

Extrinsic Laryngeal Muscles: Not only do intrinsic muscles move the larynx, eight pair of strap-like extrinsic muscles also effect laryngeal position. Extrinsic laryngeal muscles are so-named because they take origin from or insert into body parts outside the larynx. Located in the neck or beneath the mandible, extrinsic muscles connect mandible (Anatomy Lesson #26, “Jamie’s Chin – Manly Mentus”), sternum, scapula and skull to thyroid cartilage and hyoid bone. Read more about these muscles in Anatomy Lesson #12 “Claire’s Neck” or “The Ivory Tower.”

Image K identifies extrinsic laryngeal muscles but more importantly, shows upward or downward directional pulls (red arrows); four pair of extrinsic muscles depress (lower) and four pair elevate (lift) hyoid bone and thyroid cartilage. Further, the pulls are not strictly upwards or downwards. Rather, the upper four pair of muscles pull hyoid bone up and forward or up and backward; the lower four pair of muscles pull hyoid bone and thyroid cartilage down and forward or down and backward. The larynx, suspended from that wee hyoid bone, is mostly carried along for the ride!

Thus, these many muscles and their attachments allow for nuanced changes of laryngeal position during talking, laughing, screaming, singing, coughing, clicking, sneezing, snorting, swallowing, etc. Impressive!

muscles 03 Figure0025B

Image K

Thyroid Gland: Remove the extrinsic muscles and we see an important and intimate relationship between larynx and the highly vascular thyroid gland. The bilobed thyroid gland straddles the larynx, its lobes connected by an isthmus (bridge) of thyroid tissue overlying the second and third tracheal rings (Image L).

thyroid larynxFigure0070B

Image L

Vocal Folds: Next, let’s consider vocal folds. Vocal folds, commonly known as vocal cords, are paired folds of mucous membrane, each containing a vocal ligament (see Image G) and the tiny (vocalis) muscle (see image J, lower right).

Looking down the pharynx via laryngoscope (laryngoscopy), true vocal folds appear as pale thin bands (Image M). Below these, are epiglottis and tongue base. Above the folds are bumps created by mucosa overlying arytenoid cartilages. Vocal folds carry out the first and third critical functions listed below:

  • provide airway
  • exclude unwanted materials
  • generate sound

Let’s discuss each of these functions in greater detail.

Provide Airway: As muscles rotate arytenoids together, vocal folds open allowing air to flow through the lumen or glottis (Image M – left side). As other muscles rotate the arytenoids apart, the folds close and air flow slows or stops (Image M – right side). Psst: Just so you know, vocal cords lie horizontally in the neck; their vertical orientation in Image M is how they appear on a screen during laryngoscopy.

vocal folds

Image M

True vocal folds are so named to distinguish them from false folds. Find the false vocal folds in Image M. False vocal folds do not produce sound but do add resonance to the voice. Two exceptions are Tibetan Chant and Tuvan throat singing, both of these produce an undertone using small spaces (laryngeal ventricles) between true and false vocal folds (ventricles not visible in Image M).

If you find animals endlessly fascinating, get this: Male gorillas and some other primates, such as the gibbon shown in Image N, enlarge their necks by deliberately forcing air into their laryngeal ventricles. The ventricles of some primates are so large, they may extend into the thorax! In most humans, they are small.

ape ventricle 01

Image N

Remember the second crucial function of the larynx? It closes to exclude unwelcome materials. Yep, it discriminates!

Exclude Undesirables: The weird-looking epiglottis helps with the second laryngeal function, to exclude unwanted stuff from the larynx. Here is how it works: During swallowing, hyoid bone lifts and tongue depresses pushing the epiglottis downwards and backwards to cover the laryngeal inlet (Image O – black arrow). This helps prevent food, drink, spit, etc., from entering the larynx as only air is welcome (Image O – white arrow). The epiglottis also has a shape which encourages food and drink to flow around its sides and backwards into the esophagus where it belongs! Does it sometimes, fail? Well, sure, especially if we try to swallow and speak at the same time. In such instances, stuff gets into the larynx , eliciting a paroxysm of coughing! Expel the infidel!

Try this: Wait! Wait! If you have a sensitive gag reflex, don’t try this. Otherwise, do you want to feel the tip of your epiglottis? Here’s how: open mouth wide and relax tongue. Lay one (clean) index finger atop tongue. Slide it gently backward and downward along the tongue surface until you touch the rounded, thin tip of the epiglottis. Don’t gouge it with your fingernail and avoid touching soft palate, sides or back of throat as this initiates the gag reflex! Did you feel it? Good job to those who dared!

epiglottis

Image O

Generate Sounds: Last but not least, vocal folds produce sounds. During phonation, vocal folds open and close, change shape and vibrate. This brief video shows the fluid movements involved in this process – watch until the end, to see and hear the patient sing. The folds are a pale pink V in the still shot below.  The tracheal inlet is the dark hole In middle. Mounds near the top are arytenoid cartilages – these move dramatically during the film clip. The thin mobile curl at the bottom of the video is the tip of epiglottis. Oh, and the sticky material coating the vocal folds is mucus, a viscous fluid that lubricates and protects the folds. Hope you watch all of this fascinating footage!

Clinical Correlation: Please understand that if the larynx is blocked or narrowed by trauma, infection, birth defects, cancer, polyps, scar tissue, etc., the impediment must be removed or bypassed to restore the airway. Two sites commonly used for bypass are cricothyroid membrane and trachea. An opening through the cricothyroid membrane (see Image D) is a cricothyrotomy or cricothyroidotomy. An opening between tracheal rings, is a tracheotomy; if a breathing tube is inserted into the opening, then it is termed a tracheostomy (Image P).

Tracheotomy is not new as it was depicted on Egyptian artifacts dating as far back as 3600 BCE! Here’s an startling tidbit: Alexander the Great purportedly saved a soldier from suffocation by making an incision into the man’s trachea with the point of his sword! Gah! I don’t recall seeing Colin Farrel do that in Alexander.

Tracheostomy

Image P

Red flag and wee black dog are back. Must be another book spoiler! Best skip if you haven’t read ahead of Starz episodes!

redFlag

BOOK SPOILER: This quote is very pertinent to our lesson, from Herself’s fifth book, The Fiery Cross,  as it mentions structures and procedures covered in this lesson. Yay, Diana!

A cricothrotomy? Fast, and requiring no great skill, but difficult to keep open—and it might not be sufficient to relieve the obstruction.

I massaged the isthmus of the thyroid, pushing it out of the way, hard toward his head, and with my other hand, pressed the knife blade down into the fourth tracheal cartilage.

The cartilage here was U-shaped, the esophagus behind it soft and vulnerable; I must not stab too deeply. I felt the fibrous parting of skin and fascia, resistance, then the soft pop as the blade went in. There was a sudden loud gurgle, and a wet kind of whistling noise; the sound of air being sucked through blood.

… she could hear the faint whistle of air through the tube in his throat. Claire had commandeered Mr. Caswell’s imported English pipe, ruthlessly breaking off the amber stem. Rinsed hastily with alcohol, it was still stained with tobacco tar, but seemed to be functioning well enough.

Way to Hustle, Claire: Claire assiduously avoids cutting the thyroid gland isthmus, otherwise, blood would quickly flood the surgical field. She also likely pressed her knife through the soft connective tissue between 3rd and 4th tracheal rings. And, she performed a tracheostomy, inserting a pipe stem into the tracheal incision to serve as a breathing tube. Yay, Claire!

Newborn Larynx: At lesson start, I promised to consider age- and sex-related differences of the larynx. Here we go! The larynx is a tiny organ in the newborn which sits much higher in the neck (C2-C3 vertebrae) than in the adult (Image Q – infant left, adult right). The higher position of an infant larynx allows epiglottis and soft palate to touch during suckling (Image Q – left side). This important juxtaposition enables the infant, an obligate nose-breather, to simultaneously suckle and breathe. Otherwise, they would have to swallow, stop, take a breath, stop – repeat. Exhausting for such a tiny body!

Many a nursing mam knows that if her wee bairn bites down (ouch!), she can stop this by gently closing off its nostrils – the babe must let go to breathe!

It should be noted that although infant larynges are much smaller than those of adults, their vocal folds and higher lung pressure enable them to produce very audible howls,  yowls and growls!

Childhood Larynx: The larynx continues to grow throughout childhood in proportion to the remaining body with no significant differences between male and female larynges.

infant & adult larynx

Image Q

Adolescence: Then, puberty raises its provoking head, accompanied by some fascinating changes! Both sexes experience facial development, descent of the larynx in the neck, increased circumference of chest wall and greater lung capacity, all of which typically deepen and strengthen the voice. But, the larynx of a pubescent male is also exposed to a flood of androgens (mainly testosterone) which induces growth of laryngeal cartilages.

Adult Male Larynx: By 20 y.o., the average male larynx is about 40% taller and vocal folds about 60% longer than the female’s (Table A). Plates of the male thyroid cartilage meet at a 90º angle making the thyroid eminence more prominent than that of the 120º female angle (i.e., female angles are more open, so eminence is less pronounced). Male intrinsic muscles become larger and stronger and vocal folds thicker and longer leading to a drop of about one octave in voice pitch. These differences illustrate sexual dimorphism of the larynx; its responsiveness to hormones qualifying it as a secondary sex organ.

Adult Female Larynx: But, did you know that female vocal folds also respond to hormonal changes? Puberty causes the female voice to drop about 1/3 octave. But, female vocal folds also respond to hormone (progesterone and estrogens) fluctuations during each menstrual cycle becoming more edematous in the latter half which often lends the voice a breathy or husky quality. After menopause, the female voice becomes even lower due to increased circulating androgens.

After 20, the larynges of both sexes remain stable until about midlife when cartilages begin to ossify (bone replaces cartilage). Ossification is not usually a problem but one of my young readers (<20 y.o.) has ossified laryngeal cartilages and they are problematic for this person.

An astute student might ask, why would nature make the male voice deeper and stronger? Well, scientists have some suggestions about that: Perhaps, male voices have deepened over the course of evolution to signal dominance and/or to increase the speaker’s attractiveness. Studies do confirm that vocal frequencies correlate with a speaker’s hormonal status – which may or may not be attractive in a potential mate. Gals tend to like Jamie’s baritone voice. Mmphm!

Table A Mean Measurements of Male and Female Larynxes

MALES FEMALES
Height 44 mm 36 mm
Transverse diameter 43 mm 41 mm
Front-back diameter 36 mm 26 mm
Circumference 136 mm 112 mm

Sexual Dimorphism: Let’s turn to all things Outlander to witness sexual differences of the larynx. Here, in Outlander Starz episode 202, Not in Scotland Anymore, we see a near perfect example of the female Adam’s apple – or is it an Eve’s apple? Bwahahaha!

A small bump of the laryngeal prominence appears on Claire’s lovely ivory tower as she casts stink eye at stinky Duke! Love, love, love those earrings – perfect accessory for her swan-like neck!

ep-202-Adam's-apple

Compare and contrast Claire’s gentle laryngeal prominence with that of a typical male. Weil, now, perhaps not entirely typical, but certainly impressive! Jamie obligingly lifts his chin to reveal his prominent Adam’s apple (Starz episode 107, The Wedding). Lots of testosterone plus Claire help him have a vera fine time. Whinny and snort!

ep-107-Adam's-apple

The Voice: Let’s end this lesson with a brief discussion of The Voice…No, not the TV show! – just voice in general, the third important function of the vocal folds. Phonation is arguably less critical than maintaining the airway, but very important for communication and quality of life.

Roman physician Galen (130 – c. 200 CE) declared the larynx as the “first and supremely most important instrument of the voice.” Was he correct? Yes, because sounds are normally generated by vibrations of vocal folds and action of laryngeal muscles (side note: people lacking functional vocal folds can be taught esophageal speech and/or use of an electrolarynx). However, sound quality is nuanced by numerous other factors including:

  • Lung capacity
  • Extrinsic laryngeal muscles
  • Tongue movement
  • Lip action
  • Mouth anatomy
  • Pharynx, cheeks and soft palate changes
  • Paranasal sinus configuration

The cumulative effect of these factors grants to humans a voice that can be modulated to an amazing degree; never more evident than during singing. Consider the movements of lips, tongue, soft palate, etc. in this wonderful MRI of a man singing opera. The movements are astounding. Try to locate epiglottis and arytenoids. I hope you enjoy watching this internal byplay on the screen!

https://youtu.be/Q9eFqX4wvnw

Question #2: Readers have asked why our taped voices and spoken voices sound differently to our own ears? Answer: Taped voices are recorded via sound waves traveling through air before reaching our ears. The spoken voice creates vibrations transmitted to the inner ear (Anatomy Lesson # 25, “If a Tree Falls – The Ear”) mostly via bone and soft tissues, lending the voice a less tinny quality. Most folks seem to favor the spoken voice over the taped version. Make sense?

Final Outlander Fixes: Happily, Outlander gives us many treacherous throat and larynx scenes to consider!

Barely out of the chute, Claire is confronted with Captain of Dragoons’ blade at her neck (Starz episode 101, Sassenach). Good way to lose a Lovely Larynx! Fortunately for our nimble nurse, his threat is only virtual. The man’s got skills, ye ken?

ep 101 thoat slit 01

Puir not-a-wet-nurse Claire doesna get a break in episode 101. Next, Dougal jerks her around and tells her to stay with the rest of his troop of hairy-merry lads or he will obligingly slit her throat (Starz episode 101, Sassenach)! Lovely larynx at risk, again!

ep 101 throat slit 02

Remember the Sadist’s Shave? Captain Jack-Rat’s larynx is fully exposed to a vera sharp blade (Starz episode 106, The Garrison Commander). Too bad Corporal Milksop’s hand didna slip. Would have saved team Fraser a world of grief!

ep 106 larynx 01

Oops. Flip-flop and the tables are turned. Corporal Hawkins’ hand DID slip – now, he is under the blade, getting the absolute worst: a dry-neck shave (Starz episode 106, The Garrison Commander)! Vera unpleasant, especially at the hands of the foul fearsome fiend!

ep 106 larynx 02

BOOK QUOTE: Now, a few fabulous apropos lines about a dearly departed larynx from Dragonfly in Amber book:

Mary sneezed, and wiped her nose hastily with a fold of her plaid. She stared at Murtagh, eyes wide and baffled. I gazed down at the bulging saddle-bag, feeling a sudden deep chill that owed nothing to the weather outside. But it was Hugh Munro’s widow who sank to her knees, and with steady hands opened the bag and drew out the head of the Duke of Sandringham.

In Starz episode 211, Vengeance is Mine, Jamie, Claire and contrary-Mary witness Sandringham, forever separated from his smooth-speaking larynx. No more mocking jibes from this oily opportunist. Sure and true, Murtagh’s ax seeks its mark!

Diana, author of both Starz episode 211 and Dragonfly in Amber book, offers two different routes to the Duke’s Demise although the outcome is identical…. grand example of “the end justifies the means?”

The Duke, he lost his larynx,

Along with his pharynx.

The ax performed a hi-jinx.

Murtagh’s work is done!

(Let’s hear it for the Godfather!)

ep 211 Duke

Final voice Issue: According to 13 August 2016, New Scientist, and Buzz Feed, Appen, a voice recognition firm working for Google, a call for help has been posted on Reddit’s Edinburgh page for people with Scottish accents to submit recordings of themselves reading certain phrases to help train its software! Users with certain accents – particularly Scottish – have complained that voice recognition systems such as those used by Good Now and Apple’s Siri struggle to understand them. Here is a great comment to illustrate the dilemma.  Well, at least Siri got “street” right! Am I right?

sub-buzz-22604-1470315959-1

I hope you enjoyed learning about the incredible human larynx. Give a brief salute the next time you take a breath or utter a no-no word! Have a wonderful breath-taking day.

A deeply grateful,

Outlander Anatomist

Photo creds: Starz, Netter’s Atlas of Human Anatomy, 4th edition (Images B,C,D,F,G,H,I,J,K,L,M), Grey’s Anatomy, 39th edition (Table A data), www.flickr.com (Image E), www.kit10phish.wordpress.com (Image Q), www.scienceblogs.com (Image N) www.newhealthadvisor.com (Image O), www.quizlet.com (Image P), www.thisiscommonsense.com (red flag and dog), www.vocalclinic.org (Photo A), www.voicedoctorla.com (Image N), Buzzfeed

Anatomy Lesson #40 “Snap, Crackle, Pop! or How Bones Heal”

Welcome Outlander Anatomy readers! Our last lesson covered the human skeleton (Anatomy Lesson #39 “Dem Bones – The Human Skeleton”). Today’s Anatomy Lesson #40, “Snap, Crackle, Pop! or How Bones Heal” expands on bone anatomy but also addresses bone fractures and how they mend. As always, Starz Outlander images and quotes from Diana Gabaldon’s marvelous books are generously sprinkled throughout the lesson.

Last lesson began with spectacular images from Master Raymond’s hidden ossuary. This lesson, we start with images of a world famous ossuary located in Kutná Hora, Czech Republic. Known world-wide as the Bone Church, it is an ossuary (‘Kostnice’ in Czech) that houses the bones of an estimated 40,000 – 70,000 people (Image A).

bone church 01 KLS edited

Image A

Here, bones are imaginatively and artistically arranged throughout the edifice. One of the most famous displays is a chandelier, purportedly containing every bone of the adult human body (Image B).

During the thirty years’ war, aristocracy of Central Europe wished to be buried in the hallowed graveyard at this site. As the number of burials outgrew available space, remains were exhumed and stored in the chapel, then assembled into artistic presentations.

The ruffled collars beneath the candle-bearing skulls are hip bones! At the tip-top are inverted sacra (pl.). Dangling bones are humeri (pl.). Quite the room-lighter! Makes Master Raymond’s animal skulls seem almost quaint!

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Image B

Surely, these images put us in the mood to learn more about bones, although this lesson covers  bones of the living. Today’s lesson will review and present more bone anatomy and types of bone cells. Then, we will cover events that ensue when bones go snap, crackle, or pop, as well as mechanisms of healing. Let’s go!

Review of Long Bone Anatomy: Lesson #39 presented long bone anatomy, but let’s take a moment to review. Once again, the femur, is our model (Image C). The shaft of a long bone is the diaphysis. The ends that form joints with other bones are the epiphyses (pl.); these are covered with articular cartilage (ball-shaped epiphysis is head of femur). The flared region between diaphysis and epiphysis is the metaphysis. Cortical bone forms a hard outer rind enclosing the marrow (medullary) cavity. Spongy bone fills epiphyses and metaphyses and is also scattered in the marrow cavity. Depending on the bone and age of the individual, the marrow cavity is filled with either fat cells or hematopoietic (blood-forming) cells, neither of which are elements of bone. Think of them as tenants not owners!

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Image C

Periosteum and Endosteum: Periosteum is a thick fibrous layer covering the diaphyseal surface (Image D). Endosteum is a thin connective tissue layer lining the bone marrow cavity and covering all exposed surfaces of spongy bone. Both layers contain blood vessels and several types of bone cells as discussed below.

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Image D

Vascular Supply: As we learned in Anatomy Lesson #39 “Dem Bones – The Human Skeleton,” bone is living tissue and thus requires a constant blood supply such that the human skeleton receives 5-10% of the entire cardiac output (amount of blood the heart pumps per minute).

To meet this demand, large bones receive several arteries (Image E). Periosteal arteries supply periosteum and outer compact bone. Epiphyseal arteries supply blood to epiphyses (pl.). Nutrient arteries supply inner cortical bone, endosteum, and help supply epiphyses and metaphyses.

These arteries access a bone via foramina (channels) that traverse compact bone to reach their respective turfs, then break into capillary beds where oxygen and nutrients are exchanged for carbon dioxide and waste products. Corresponding veins form and blood flows back to the heart. Round and round and round it goes…..

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Image E

Nerve Supply: You may be surprised to learn that mineralized bone (organic matrix plus inorganic minerals – see Lesson #39) does not have pain receptors. Hum…if this is true, then why does a broken bone hurt so badly? Because periosteum and endosteum as well as articular surfaces are richly supplied with pain receptors (nociceptors). If these structures are compromised as with a fracture, then pain is severe!

Image F nicely illustrates nerve and blood vessel distribution in cortical bone and margin of the marrow cavity. Anatomy typically color codes arteries red, veins blue, and nerves yellow. The tiny yellow lines indicate that nerves follow blood vessels through cortical bone to the endosteum. Although not shown in Image D, nerves also follow periosteal arteries to innervate the periosteum.

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Image F

Bone Cells: As mentioned above, bone contains several cell types including osteogenic cells, osteoblasts, osteocytes, and osteoclasts (Image G). These cells are located in periosteum, endosteum, or within mineralized bone. Again, although hematopoietic cells or fat cells fill spaces between spongy bone and within marrow cavities, these are not bone cells.

Osteogenic cells are stem or parent cells giving rise to osteoblasts (Image G); they reside in periosteum and endosteum.

Osteoblasts: From Greek osteo- meaning bone + blastanō meaning to germinate, osteoblasts produce collagen and other proteins as part of the organic matrix. These proteins are released into the extra-cellular environment where minerals deposit around them. Together, the organic matrix provides tensile strength and inorganic minerals provide compressive strength. As to their bulk, organic proteins represent 10% of bone mass with the remaining 90% being inorganic mineral. Osteoblasts reside in periosteum and endosteum.

Osteocytes: In the course of production and secretion of organic matrix and its subsequent mineralization, osteoblasts become “imprisoned” within bone and are renamed osteocytes. Located in compact and spongy bone, osteocytes help maintain the mineralized bone. Further, the mineralized matrix with imprisoned osteocytes is organized into cylinders of bone known as osteons (Haversian systems). A bone such as the femur contains millions of osteons but details about these units must await a future lesson.

Osteoclasts: Giant, multi-nucleated cells, the osteoclasts, are formed by the fusion of macrophages (Anatomy Lesson # 37, “Outlander Owies Part 3 – Mars and Scars”). Found in endosteum, their duty is to dissolve bone.

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Image G

As you might imagine, a good deal of coordination among the various bone cells is required to ensure homeostasis (balance) between bone production, maintenance, and resorption. For example, as a bone grows in circumference due to periosteal osteoblast activity, osteoclasts of the endosteum remove bone from the inside so the thickness remains fairly constant, a highly regulated process.

Image H shows in detail the distribution of bone cells in periosteum, endosteum and in compact bone.

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Image H

Next, let’s do something really daring and look at a microscopic image of bone cells as viewed through a light microscope (Anatomy Lesson #34 – “The Amazing Saga of Human Anatomy”). Please understand that microscopic anatomy, better known as histology (Greek histo- meaning “tissue” + ology meaning “to know”), is a challenge for most students. Watch this fun video by Harvard medical students as they lament about studying “histo!”

https://www.instagram.com/p/BEYogsIuTPz/

Ha ha! Very clever, medical students! But, you readers might respond the same way looking at a magnified image of a shard of spongy bone (Image I). This image is of a very thin slice of bone that has been stained blue and pink with H&E (hematoxylin = blue + eosin = pink). The so-called H&E stain is the most commonly-used histo stain in the US.

So, what do we see in Image I? The dense pink vertical band is a spicule of ossified spongy bone. The oval cells with pale nuclei along the left border of the shard are osteoblasts laying down a pale layer of unmineralized organic matrix (osteoid). The right border of the spicule show two large multi-nucleated osteoclasts busily dissolving bone – one such interface is a distinct divot indicated by the black arrowheads. Such divots are termed Howship’s lacunae (named for John Howship, a British anatomist). Several irregularly-shaped nuclei are scattered within the bony spicule – these are osteocytes encased in ossified bone.

That’s pretty much it! Being competent at recognizing cells and extracellular substance is based on pattern recognition. Looking at many examples of a given tissue is very useful in obtaining said competence. If you think this is impossible, understand that anatomical pathologists make their living looking at and diagnosing diseases from thousands of such tissue slides.

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Image I

Bone Fractures: Time for snap, crackle, and pop, and I dinna mean Rice Krispies! Compressive strength from mineral deposition and tensile strength from organic matrix give normal bones the ability to behave elastically. If trauma overcomes this elasticity, then bones fracture!

Bone fractures fall into two major categories: mechanical bone fractures caused by high force impact or stress, and pathological fractures caused by disease.

Pathological Fractures: Diana presents a fabulous case of fracture caused by disease in Colum. The Laird of clan MacKenzie is haunted by the aftermath of a pathologic fracture and accompanying deformities due to Toulouse-Lautrec syndrome (Starz episode 208, The Fox’s Lair).

Outlander book informs readers that at 18 y.o., Colum took a bad fall breaking the long bone (femur) of his thigh that subsequently mended poorly. Other skeletal anomalies quickly ensued. Diana explains in Dragonfly in Amber:

Legs crippled and twisted by a deforming disease, Colum no longer led his clan into battle…

…He glanced dispassionately down at the bowed and twisted legs. In a hundred years’ time, they would call this disease after its most famous sufferer—the Toulouse-Lautrec syndrome.

Read Anatomy Lesson #27, “Colum’s Legs and Other Things too!” for details about this rare syndrome (1.7 per million births). Of course, there are also many other diseases leading to pathological fractures. Nowadays, the most common in the US is osteoporosis.

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Mechanical fractures: High force impact or stress cause bones to snap. Different types of bones (e.g. short vs. long) often exhibit characteristic fractures. This lesson will consider fractures of long bones using the femur again as our example. Fractures are generalized into six different categories:

  • Closed fracture – bone is broken but overlying skin is unbroken
  • Open fracture – better known as a compound fracture, broken bone pierces the skin
  • Simple fracture – bone is broken but no other tissues damaged
  • Complex fracture – sharp fracture edges damage surrounding soft tissues
  • Complete fracture – bone breaks completely across the shaft
  • Incomplete fracture – bone is partly broken but remains in one piece

Then, fractures are named according to features of the break (Image J).

  • Normal – left image is the normal femur
  • Transverse – break crosses the shaft horizontally
  • Oblique – break crosses shaft at an angle
  • Spiral – torque on the broken halves twists these in opposite directions
  • Comminuated – bone is broken into four or more pieces (including main body of the bone)
  • Avulsion – a piece of bone is torn away usually by pull of a muscle tendon
  • Impacted – bone parts are driven together, also known as a buckle, or compression fracture
  • Fissure – crack along one side of the shaft
  • Greenstick – incomplete break through the shaft. Analogous to breaking a stick of green wood.

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Image J

Fracture Healing: Fracture healing is the process by which the body repairs a broken bone and what a process it is! Several overlapping steps occur, different descriptors are used, and times may vary depending on the bone, but the general sequence is (Image K):

  1. Hematoma Formation (days 1-5): Bone fractures tear blood vessels, and periosteum and endosteum. Blood pours from the damaged vessels forming a hematoma (blood clot) between the fractured surfaces. Blood flow in intact vessels increases such that an army of white cells are delivered for defense and repair.
  1. Soft Callus Formation (days 3-40): Gradually, a bridge of cartilage and collagen replaces the hematoma and unites the broken ends. The cartilage bridge is made by chondroblasts (cartilage-generating cells) and is termed a soft callus.
  2. Hard Callus Formation (days 30-80): During this stage, cartilage of the soft callus is gradually replaced with new, woven bone (cartilage does not change into bone) and the site is renamed a hard callus. But, woven bone is immature and not as strong as mature compact bone. Mild exercise is often resumed during this phase.
  3. Bone Remodeling (days 80-100): If all goes well, the hard callus is gradually replaced with normal, mineralized compact bone that remodels to align with muscle pull and mechanical stress. Exercise promotes this process which is typically 80% complete within three months. But, depending on the bone and the fracture, step four can take up to 18 months.

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Image K

Normal fracture healing requires the following:

  • Adequate blood supply: Oxygen and nutrients must be delivered to the repair site and carbon dioxide and waste products removed; these processes require blood vessels. Thus, re-vascularization occurs at the fracture site.
  • Fracture stabilization: Excessive movement of the fractured bones interrupts callus formation so fractures are immobilized with a variety of ingenious devices such as casts, rods, plates, screws, and external fixators.
  • Adequate nutrition: On average, a fracture heals by 12  weeks. However, healing times depend on which bones are broken, severity of the breaks, age (younger folks usually heal faster), and nutrition. A vitamin sandwich (Image L) looks funny but animal and human studies show that fracture healing improves with supplements of Vitamins C, D, and E, as well as calcium and amino acids. Details of these experiments exceed our lesson goals, but understand that many average diets are marginal in these substances. So, be sure to consult with your physician about supplements while healing a bone fracture.
  • Rehabilitation: Immobilization of a fracture contributes to muscle wasting. Physical therapy can provide critical support in re-building muscle and encouraging proper bone alignment. This includes weight-bearing on a fracture after it has mostly healed in order to build bone strength.
  • No-No nicotine: Studies are pretty clear that nicotine in any form hinders the process of bone healing. Avoidance behavior!

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Image L

Now for some real “fun.” With Starz images, let’s use applied anatomy to consider mechanical bone fractures and healing. Starz Outlander episodes offer two excellent examples of bone fractures, both are compound in type.

A workman is admitted to L’Hôpital des Anges in Paris (Starz episode 204, La Dame Blanche). He screams in agony because he has suffered a compound fracture of the right tibia (Anatomy Lesson #27, “Colum’s Legs and Other Things too!”). The skin is open and the upper part of the broken tibia is clearly visible at the red arrow.

This injury hurts like holy toothpicks because tears of periosteum and endosteum stimulate nociceptors (pain receptors). Then, muscles spasm as they attempt to stabilize bony fragments, upping the pain meter. And, adding insult to injury, a compound fracture rents the skin and we all ken how sensitive skin is to pain! All around, an agonizing situation.

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So, what does a good hangman do to ease his patient’s discomfort? Why, he hammers a nail into the side of the poor fellow’s knee, of course! What else? Presumably a type of primitive acupuncture, it momentarily halts the patient’s agony; mayhap from PTSD?

A quote from Dragonfly in Amber:

Monsieur Forez was at work today. The patient, a young workman, lay white-faced and gasping on a pallet. …The leg, though, was something else… Sharp bone fragments protruded through the skin … “Here, ma soeur ,” he directed, taking hold of the patient’s ankle. “Grasp it tightly just behind the heel… Monsieur Forez brought the point of the brass pin to bear …he drove the pin straight into the leg with one blow. The leg twitched violently, then seemed to relax into limpness.

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Monsieur Forez enlightens Claire regarding this startling exhibit of bedside manner (from Dragonfly in Amber):

“There is a large bundle of nerve endings there, Sister, what I have heard the anatomists call a plexus. If you are fortunate enough to pierce it directly, it numbs a great deal of the sensations in the lower extremity.”

Stop! I must pick at a wee bone: During the episode, Mr. Forez explains to Claire that anatomists describe a nerve at the inside of the knee which, if pierced, briefly anesthetizes the leg (Anatomy Lesson #27 – “Colum’s Legs and Other Things too!”). So, the human grease-guy whacks a 4” nail into the side of the workman’s knee for pain relief!

So this is what troubles me: the nail pierces skin near the saphenous nerve (a branch of the femoral) which, unfortunately, supplies only skin of the area and does nothing for bone pain. The correct nerve to pierce would be the tibial nerve, a branch of the sciatic; but, both of these nerves are in the back of the thigh! From the thigh, the tibial nerve sends fibers to the tibia in concert with its nutrient artery where it innervates endosteum and periosteum. Ergo, for this technique to work, the good Monsieur must pierce the tibial nerve in the back of the thigh.

I canna vouch for the efficacy of nail piercing, which seems a wee bit harsh, but I can question Forez’s anatomists and their data base. Soon after the shock of piercing subsides, the patient resumes screaming so I canna think it verra efficacious. Gah! Back to the dissection lab for those anatomists! But, I must say, the special effects are superb!

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Next, we will consider another compound fracture, arguably the most infamous of the Starz series. The Wentworth Smack-Down delivered high force impact causing mechanical fractures of Jamie’s left hand bones (Starz episode 115, Wentworth Prison). Let’s do a walk through of these fractures.

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Heading to Outlander book, Diana enlightens us with these quotes:

Luckily the thumb had suffered least; only a simple fracture of the first joint. That would heal clean. The second knuckle on the fourth finger was completely gone; I felt only a pulpy grating of bone chips when I rolled it gently between my own thumb and forefinger…

The compound fracture of the middle finger was the worst to contemplate. The finger would have to be pulled straight, drawing the protruding bone back through the torn flesh. I had seen this done before—under general anesthesia, with the guidance of X rays.

We can easily deduce from Diana’s description that, at a minimum, Jamie’s hand suffered:

  • Simple fracture of the first phalanx of thumb.
  • Communiated fracture of the ring finger (4th finger in English system; 3rd in US system – see Anatomy Lesson #22, “Jamie’s Hand – Symbol of Sacrifice”) – proximal and middle phalanges smashed into bony bits.
  • Compound fracture of middle finger – appears to be middle phalanx of the middle finger.

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Like any combat nurse worth her salt, Claire cleanses Jamie’s wounds. She has no modern isotonic fluids or antibiotics, so she cleans his compound fracture with (no doubt) sterile water, perhaps containing a wee dram of alcohol for sterilization?

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Next, Claire ponders the damage and then re-aligns and resets the bony fragments (Starz episode 116, To Ransom a Man’s Soul). And again from Outlander book:

I began to lose myself in the concentration of the job… deciding how best to draw the smashed bones back into alignment.

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Now, as we learned above, a compound fracture tears surrounding flesh and skin. So Claire carefully closes the wounds with sutures (Starz S.2, introductory image) to exclude pathogens and reduce blood loss.

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Earlier in this lesson, we read that movement of a new fracture interferes with callus formation. So, various devices are used to immobilize fractures as they heal.

Ever resourceful Claire (or the monks?) devises an external fixator for Jamie’s smashed hand in the form if a very clever wire/leather, linen, and wood device! External fixation is a surgical treatment used to stabilize bone and soft tissues at a distance from the injury. So, check out the amazing invention (Starz episode 116, To Ransom A Man’s Soul) to immobilize Jamie’s hand! The middle finger is reset and stitched. The communiated and most severely wounded ring finger is stitched and splinted against the small finger. Brava, Madam Sassenach!

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Jamie’s hand care is not yet complete! Claire provides physical therapy in the form a rag ball she made. Squeezing the ball helps Jamie regain hand mobility and strengthen the knitting bones as he and Murtagh plan how best to skewer BJR (Starz episode 203, Useful Occupations and Deceptions)!

In case you forgot from earlier in this lesson, exercising a repairing bony callus augments the ossification process, so Claire’s rehabilitation plan is spot on!

Two quotes from Diana’s Dragonfly in Amber:

It really wasn’t too bad; a couple of fingers set slightly askew, a thick scar down the length of the middle finger. The only major damage had been to the fourth finger, which stuck out stiffly, its second joint so badly crushed that the healing had fused two finger bones together. The hand had been broken in Wentworth Prison, less than four months ago, by Jack Randall.

He had regained an astounding degree of movement, I thought. He still carried the soft ball of rags I had made for him, squeezing it unobtrusively hundreds of times a day as he went about his business. And if the knitting bones hurt him, he never complained.

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And, pithy quotes from Diana’s Dragonfly in Amber remind us that months later, Jamie’s hand is still not whole (Starz Season 2 opening images), so clever caring Claire applies her personal version of massage therapy… a task that she and he undoubtedly relish! Hee, hee.

I crawled in beside him and took up his right hand, resuming my slow massage of his fingers and palm. He gave a long sigh, almost a groan, as I rubbed a thumb in firm circles over the pads at the base of his fingers.

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Thus ends Outlander compound fractures and healing. Whether bone breaks or skeletons, people are endlessly fascinated by bones and the stories they tell. Book readers will recognize this poignant commentary from Dragonfly in Amber as Jamie and Claire find the bony inhabitants of an unknown cave in France.

He turned again then to the two skeletons, entwined at our feet. He crouched over them, tracing the line of the bones with a gentle finger, careful not to touch the ivory surface. “See how they lie,” he said. “They didna fall here, and no one laid out their bodies. They lay down themselves.” His hand glided above the long arm bones of the larger skeleton, a dark shadow fluttering like a large moth as it crossed the jackstraw pile of ribs.

Now, I have my own bone story to share. The following is a true event underscoring the amazing capacity of bones to heal. During WW II, my father was a welder of Liberty Ships in California. When I was 18 months of age, neighborhood kids accidentally ran over me and the trauma snapped off the head (ball-shaped epiphysis) of my right femur. Local physicians were unable to help so they sent us to the Treasure Island Naval Base where many of the best US physicians were stationed to assist with the war effort.

Those docs had never set a child’s femoral head before, but they courageously reset my leg, placed me in a 3/4 body cast, and prepared my parents for the bad news: the blood supply to the femoral head was likely severed, the femoral head would become necrotic (die), and the hip would freeze into an immobile joint. I would not walk normally, if at all.

Well, the good news is that my femoral head did not perish! Somehow and somewhere, an arterial supply survived. Although my colleagues and I share theories about which vessel might have remained intact, no one knows for sure.

Image M was taken in 1944 at Stinson Beach, CA, six months after the injury (like the artery, my appetite clearly remained intact <G>). Observe that the right leg is slightly rotated outward (externally), a classic stance following a femoral head fracture.

Today, the only residual is my right leg is 3/8” shorter than the left. Otherwise, nada! I am able to exercise vigorously and with no noticeable deficit. Blessings to those unknown healers who helped the wee bairn of a common laborer!

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Image M

Our lesson on how fractures heal has come to an end. After two lessons about the skeleton, there remains much more to be studied, so we may revisit this topic at a later date.

A few last thoughts: Remember, bone is a dynamic tissue which constantly remodels itself throughout life. Individual bones are organs that collectively constitute the skeleton, our internal support system. Bone cells create, maintain, and destroy bone tissue to our benefit.

Bones have been prodded, examined, healed, revered, saved, feared, embellished, and cherished. Not all of this lesson is about happy stuff, so let’s end with this slightly irreverent image from the bow of the Titanic.

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Image N

Dem bones, dem bones!

A deeply grateful,

Outlander Anatomist.

Photo creds: Starz, Outlander Anatomy archives (Image M), www.anatomy-medicine.com (Image F), www.askabiologist.edu (Image J), www.apps.carleton.edu (Image B) www.boneandspine.com (Image C), www.geneticliteracyproject.org (Image L), www.medcell.med.yale.edu (Image I), www.reddit.com (Image A), www.en.wikipedia.org (Image E; Image H), www.everythingfunny.org (Image N), www.commons.wikimedia.org (Image G) ,www.studyblue.com (Image D), www.ippe2ools.blogspot.com (Image K)