Anatomy Lesson #11: Muscles of Facial Expression
We humans communicate via written word, oral articulation, body language and facial expression. Welcome to Anatomy Lesson #11 as we learn about muscles that give expression ta the face; it telegraphs more emotional content than perhaps any other body part (photo A) and it’s probably the main way the world recognizes each of us. WARNING: if ye are a wee bit squeamish, this post contains images o’ the skull and facial muscles sans skin. But, if ye concentrate on the science queasiness is usually replaced by the intellectual challenge of learning. I promise. Be brave!
This lesson starts and ends wi’ Jamie. Why? Weel, can ye name an actor wit’ a more expressive face? Frankly (no not that Frank), I think our ruadh Jamie ranks up there with expressives such as Sir Anthony Hopkins and Sir Laurence Olivier. His range of facial expression is so great that there are times he looks like a different actor! Check the next image: at first glance, his gorgeous countenance appears serene but look again: it fair beams wi’ intelligence, determination, calculation and wit (Starz episode 4, The Gathering)!
And, I’ll be sayin’ that Jamie is no afraid ta use his muscles of facial expression if they yield keener insight inta his emotional state – here as a warrior furiously fighting the Grants (Starz episode 8, Both Sides Now).
OK – on ta the lesson: Several skull bones provide attachments fer muscles o’ facial expression (Photo B). Please palpate (feel) these on your own skull: the bone o’ your forehead is the unpaired frontal bone; at the back of the skull is the unpaired occipital bone; the cheeks are mostly the paired zygomatic bones (Anatomy Lesson 8); the upper teeth are seated in paired maxillary bones; the lower teeth anchored into the unpaired mandible; the bridge of the nose is formed by paired nasal bones. Try this, grip the bridge of your nose wiggle it – normally, it doesna move. Now, work yer fingers toward the tip until you feel bone gie way ta soft tissue – at this point the nasal bones are joined ta the nasal cartilages which ye can easily wiggle.
The human face has 20+ pairs of muscles of facial expression (Photo C – not all muscles are shown). Little wonder that the face can display an astonishing range of emotion wi’ more than 40 individual muscles plus working in groups for combined effects!
Ye should ken that these muscles vary from person ta person. Most are thin, flat and subcutaneous (just under the skin). Some attach to skull bones, dermis of the skin (Anatomy Lesson 5 & Anatomy Lesson 6) and/or blend wi’ other facial muscles. A few have no bony attachments at all. As they contract, the skin wrinkles at right angles to the direction o’ the muscles fibers. They also have strange names that are pronounced like they are spelled.
The muscles o’ facial expression develop from the same embryonic region and all are innervated by the paired facial nerves, a.k.a. Cranial Nerves VII (Roman numeral), which arise from the brain (Photo D). Each nerve leaves the skull via a hole (foramen) just below the ear canal and breaks into 5 branches that supply the muscles o’ facial expression. The large bumpy orange mass at the side o’ the face is the right parotid (major salivary) gland.
We anatomists love using devices and mnemonics to help us remember the myriad o’ names and details o’ the human body. It’s a mess o’ info ye ken? Here is a fun one ta recall the branches of the facial nerve (Photo E); it’s a teaching device – not intended ta intimidate the wee lassie. I like this acronym to recall the branches: To Zanzibar By Motor Car!
The paired Facial Nerves signal the muscles of facial expression to contract! If a Facial Nerve is compromised then the facial muscles are paralyzed on the same side; this condition, known as Bell’s palsy, is demonstrated in the archival photo of a gentleman from the late 1800s (Photo F). The right side o’ his face (on your left) has lost expression: he canna close the eyelid, his mouth droops and his smile (nasolabial) fold is flattened. Bell’s palsy is a difficult, debilitating and depressing condition because, as noted earlier, our face is how we face the world. To honor contributions by Scots ta medical science (there are many) the syndrome bears the name of the man who first described it: Dr. Charles Bell (1774-1842) surgeon, anatomist and graduate of The University of Edinburgh. Pertinent to this topic and based on his anatomical knowledge, in 1806 Bell published “Essays on the Anatomy of Expression in Painting” for the instruction of artists.
Now, back ta the muscles of facial expression: for simplicity, I have divided the face into regions, naming their facial muscles and providing examples of Jamie, Claire and a few other cast members. Please ken that I canna cover all the muscles o’ facial expression nor all the cast for such a post would be way toooo long.
Region 1, Forehead/Eyebrows: Four paired muscles act in this region but we will consider three pairs (Photo G) – frontalis (black arrow), occipitalis (blue arrow) and corrugator supercilii (purple arrow).
Fibers o’ the frontalis muscles are oriented vertically from a connective tissue sheet overlying the skull (galea aponeurotica – grey in Photo G) to the dermis o’ the eyebrows. Frontalis muscles raise the eyebrows and wrinkle the skin of the forehead as in asking a question or expressing concern. Now, several o’ ye hae begged me ta do some anatomy on Dougal – so here’s Dougal wi’ both frontalis muscles contracted as he interrogates Claire (Starz episode 5, Rent).
The paired occipitalis muscles (Photo G) are oriented vertically from the occipital bone ta the galea aponeurotica. When they contract, the forehead is pulled backward. As Claire causes kissus interruptus, Jamie contracts his occipitalis muscles and his forehead and scalp are pulled backward – Surprise! Ye are gonna have to wait Jamie (Starz episode 7, The Wedding)! Watch the episode again (as if ye need an excuse) ta see his occipitalis muscles in action and ye’ll ken what I mean. Claire, what a tease! Jamie, if the lass willna do her duty, in the interest of science I’m sure there are plenty of others willing to step in…just sayin’!
Fibers o’ the paired corrugator supercilii (what a name!) are oriented diagonally from the frontal bone ta the dermis between the eyebrows (Photo G). As they contract the brows “knit” together creating vertical wrinkles between the eyebrows as in worry, frown or puzzlement. Here Claire watches as Geordie is near death at the tynchal (Starz episode 4, The Gathering).
Now, here’s a more complicated facial expression: Jamie watches a foul redcoat deserter assault Claire (Starz episode 8, Both Sides Now). Which muscles o’ his forehead are contracted?
Weel, turns out both the frontalis (medial parts only) and corrugator supercillii muscles are contracting simultaneously ta reflect terror, despair or helplessness. Jamie looks ta be in agony here. Good job if ye named either muscle!
Region 2, Eyelids: One pair of facial muscles operates the eyelids, the orbicularis oculii (Photo H – black arrow); these are paired elliptical muscles attaching to frontal and maxillary bones and to a fibrous band at the inner corner o’ each eyelid. Orbital loops of each orbicularis oculus extend under the brows, reach the temple and overlay the zygomatic bone. Palpebral loops extend into the upper and lower eyelids. Contraction of these muscles closes the eyelids to varying degrees. (NOTE: the eyelids are opened by muscles that do not belong ta muscles o’ facial expression.)
Here is a funny scene from Starz episode 5, Rent: Dougal is telling the Highlanders about auld granny Mary asking her husband what he was thinking “when ye first saw me nipples!” Note the crow’s feet at the corner o’ his right eye? These are caused by contraction o’ the right orbicularis oculus muscle – here in an expression of mirth. Dougal is so into his story that he even drools! It happens quickly, but ye can see a wee sliver o’ saliva after it drops from his mouth (red arrow). Verra funny!
In the same episode Jamie tells Claire: “Dinna worry – trees are safe, Sassenach” (much safer than Uncle Dougal. Aye?). Here only the orbicularis oculi of his lower eyelids are contracted giving him the Fraser cat’s eyes and broad cheekbones that Herself attributes to Jamie. And, while we are at it, this image shows Jamie’s chin dimple verra well (the Outlander books describe Jamie as having a strong jaw and chin but no chin dimple – works fer me, though)!
Here’s Claire’s wi’ her eyelids closed because the palpebral parts o’ both orbicularis oculi muscles are contracted. She’s just told Jamie that his dirk is too long and heavy fer her (Starz episode 8, Both Sides Now). Snort! Rupert replies that the lassies say that ta him all the time so Claire gives him a look of mild disgust. Naughty Rupert!
Region 3, Upper Lip: A whopping five pair o’ muscles operate the upper lip (Photo I)! We’ll cover three of these: zygomaticus major (purple arrow), levator labii superioris alaeque nasii (green arrow) and rizorius (blue arrow). An unpaired muscle, orbicularis oris (black arrows) operates both upper and lower lips – we will cover it here, as well.
Zygomaticus major reaches from the zygomatic bone to the corner (commissure) o’ the lips. Its contraction pulls the commissure upward as in a smile. Jamie shows a good one here (Starz episode 5, Rent). Claire has declared that Angus can “kiss her bloody English ass.” He canna help but grin – she’s a spirited lass and he likes her potty mouth. Hey, hey, did ye also ken that he has cheek dimples? Too cute!
Although Levator labii superioris alaeque nasi muscles have the longest name of the 600+ skeletal muscles o’ the human body, they are pretty small. The name is Latin for “lifter o the upper lip and wing o’ the nose”. Each muscle arises from the maxillary bone and divides into two slips – one to the upper lip and the other to a nostril. In plain English, the lip-slip lifts the lip into a snarl and has been tagged “The Elvis Muscle”. Weel, Rupert beat Elvis out by two centuries as he snarls at Claire “Horse, my cock” (Starz episode 4, The Gathering)! Yep, that’s his right LLSAN muscle contracting.
The other slip o’ levator labii superioris alaeque nasi flares the nostril (red arrow). It’s quick but here Jamie flares his nostrils as he tells Claire he reckons they will be riding all that night and the next one too (Starz episode 1, Sassenach)! There is a better one o’ his flaring’ nostrils but I’ll be saving that fer a later lesson!
Each risorius muscle reaches from the parotid glands (Photo C) to the commissure o’ the lips. As they contract, the mouth pulls into a grim, flat smile – here, Jamie kens just how pissed Claire is about the marriage contract (Starz episode 6, The Garrison Commander)!
Finally, the unpaired orbicularis oris circles the mouth but isn’t a sphincter; it is a complex of four interlacing quadrants of muscle. It contracts ta closes the mouth and pucker the lips. It is used in a kiss, to play brass instruments or ta spit. See it in action here as Jamie warns Claire that he will brook no dissent from her – aye, she is coming wi’ him (Starz episode 1, Sassenach)! If she willna walk then he will pick her up and throw her o’er his shoulder! Does she want him to do that? Her mouth says no but ye can bet her heart says, oh aye!
And here is Claire’s orbicularis oris muscle getting into the act as she puckers up and spits in the face of BJR (Starz episode 1,Sassenach)! Doesna matter if he does look like Frank, the smart lass wants nothing to do wi’ this bloody bastard!
Region 4, Lower Lip: The lower lip has 4 paired muscles that activate it (Photo J). We will cover three: mentalis (green), depressor anguli oris (purple arrow) and platysma (blue arrows). The lower lip is also moved by the unpaired orbicularis oris but it has already been covered.
The mentalis muscles contract to pucker the skin o’ the chin. See Mrs. Fitz (red arrow) asking God to bless Claire for saving her nephew, Tammas Baxter (Starz episode 3, The Way Out). Just so ye ken the lips are everted by other muscles including levator labii superioris alaeque nasi and orbicularis oris. Mrs. Fitz adores Claire. She would have the Miracle Worker sit fer a portrait if it were up ta her!
The paired depressor anguli oris passes from the mandible to the orbicularis oris muscle (Photo J). As they contract, the lower lip is drawn down; Claire contracts both o’ hers ta demonstrate her disgust at the British treatment of the Scots (Starz episode 6, The Garrison Commander). Her outspoken words place her in the hands o’ BJR.
Each paired platysma is a long, thin flat muscle that begins in the dermis near the 2nd rib, passes over the jaw and ends in the dermis near the lower lip; it has no bony connections and is sometimes listed as a muscle o’ the neck (Photo J).
Have ye noticed how a horse can quiver its skin ta rid itself of insects? This muscle is equivalent ta the human platysma. As our platysmas contract, they pull down the lower lips and wrinkle the skin o’ the neck conveying the expression of a grimace. Here we see Jamie with his platysmas contracted (red arrows) after he hoists Dougal o’re his shoulder because his uncle was playing dirty shinty (Starz episode 4, The Gathering)!
Region 5, Cheek: Each facial cheek contains one muscle, the buccinator (Photo K – black arrows); it hides deep ta the risorius muscle. Each muscle starts near the back of the jaw and blends wi’ the orbicularis oris. It’s known as the bugler’s muscle fer guid reason; try this, fill yer mouth wi’ air and push out yer cheeks. The bulging cheeks contain the buccinators. Now, draw yer cheeks inward ta blow out the air; ye just contracted yer buccinators. Congrats!
Here, Jamie’s right buccinator (green arrow – canna see the left one) is expanded as he contemplates one o’ a bazillion questions thrown at him.
Weel, now, just in case ye think that animals canna have facial expression take a wee keek at these next four images (Starz episode 5, Rent). This is a scene where Rupert has just told the Highlanders how he was stuck between hairlip Chrissie and sweaty Nettie trying ta decide which one to swive first. Sassy lassie Claire declares that she believes his left hand is jealous of his right followed by a moment of tension where everyone, especially Jamie, awaits Rupert’s Response (sounds like the title o’ a book – Aye?). Jamie gets the joke right away.
Takes a few seconds but then the other Highlanders get her joke! Jamie’s zygomatic majors are contracted here in a big ol’ grin! Even Brimstone (I think its Brimstone) starts ta get the joke!
Brimstone is really getting into it along wi’ Jamie! BTW did ye notice the beautiful cutwork on Brimstone’s bridle? Dinna know who did the leather work but it’s almost as lovely as Claire’s wardrobe which Mrs. Fitz puts together sometime between supper after the boar hunt and first light the next day as they head off ta collect the rents! (That Mrs. Fitz sure is a miracle worker herself). I figure the covered wagon they take is to carry Claire’s wardrobe – it would put a queen ta shame!
And finally, the full horse laugh from Brimstone. Och, ye are a witty one, Claire!
Now I promised ye that I would begin and end wi’ Jamie. I have pondered how it is that Starz Jamie has such an expressive face. It could be because he has more muscles of facial expression than most people; aye, it happens and I have seen examples in the dissection lab. Mayhap his facial muscles are more highly innervated giving greater control o’er them. Perhaps he is a keen observer of human emotional nuance. Possibly he is highly intuitive which allows him to feel his way through a character more than most actors. Or, his emotional intelligence could derive from some combination of the above. Whatever the explanation, we viewers are the lucky beneficiaries of his acting skills. So, thank ye Jamie!
Here’s a terrific example from Starz episode 3, The Way Out as Claire unties Jamie’s stock to check his gunshot wound: with little more than sideward glance, a slight narrowing o’ the eyelids and a wee tug o’ the lips, Jamie conveys extreme discomfort and smoldering UST! Och, if ye dinna know what it means, check www.urbandictionary.com!
I hope ye enjoyed learning about the verra important muscles of facial expression, especially Jamie’s!
And fer those who are new to my blog, a note of explanation: I follow the convention of using the character’s names rather than the Starz actor’s names. This gives the cast at least one degree of separation and a wee bit o’ respect as I dissect their bodies with words! I hope ye all understand!
The deeply grateful,
Image credits: Starz, Netter’s Atlas of Human Anatomy, 4th ed., Clinically Oriented Anatomy, 5th ed., Hollingshead’s Textbook of Anatomy, 5th ed., www.Wikipedia.org