Heads Above The Rest!; Exploring The Science and Art Of The Equine Head for Sculpting: Part 12

Introduction

Welcome back to this 20–part series on understanding and sculpting the equine head from an anatomical, artistic, and evolutionary point of view. So far we've been talking about its anatomical and evolutionary attributes, and we'll continue this line of discussion in this Part 12.

But before we do, we should know that we'll now be exploring some anatomical features that typically go glossed over or outright ignored. Ignored? Yes! Ignored! Many references actually dismiss certain anatomical features in order to feed the lopsided focus on muscles and bones! And these omitted tidbits may be different between different references, or typical, like those we'll be discussing now. It's important to know that each anatomical diagram or text is merely one person's arbitrary interpretation trying to make orderly sense of anatomy which, in life, is organic, chaotic, and messy, and nothing like the neat bundles, delineations, and distinctions we find in diagrams and descriptions. This is why anatomy references can differ between each other. For example, certain muscles can be individually named in one text or instead be considered part of another muscle in another, and so simply not "exist." What's more, there exist whole components of his build that typically go neglected as the author attempts to simplify what's inherently very complex. In this sense, every anatomical reference is a "dumbed down" version of life so if we don't "fill in these blanks" then not only will our sculptures be defective by omission, but our anatomical understanding will be woefully incomplete as well.  

For these reasons, we should be familiar with many anatomical references to round out our mental library—and the more the merrier! We also need to engage in proactive education to "fill in those gaps" and constantly question every anatomy reference we employ. We should also regard each one with an adaptable mind, remembering its inherent subjectivity. Indeed, there are many aspects of anatomical references we need to regard critically, and keeping them in perspective helps us to make better use of them. 

So the point is this: anatomy is so much more than muscles and bones. Honestly, these oft overlooked or discarded features offer so much for increasing the authenticity of our sculptures, so with that in mind, let’s explore them further!…

Fascia

Now let me be straight up here—I'm an enthusiastic, unabashed fan of fascia! Why? Well, because we can think of fascia as the "tissue of life" itself. We have bone, we have muscle—but we also have fascia! The Great Trinity of Anatomy. In fact, fascia is easily argued to be as important as muscles and bone—yet it’s the most overlooked and disregarded feature of anatomy! For example, in a travesty of oversight, it's typically stripped away in dissection and largely omitted from subsequent diagrams and descriptions as though it was garbage tissue. So we need to take the extra effort to amend that knowledge gap because without a thorough appreciation of fascia, our understanding of equine anatomy will be acutely impaired, and so our depictions will always lack that "special something" so natural, accurate, and lively in the real thing. 

What's fascia? Well, it's a fibrous connective tissue made mostly of collagen, with fibers as strong as steel, that can be various degrees of slipperiness, stretchiness, or stiffness depending on its function. Holding the entire body system together (including gluing the skin down), this fibrous network facilitates and governs strength, balance, coordination, flexibility, adaptation, and movement, and is the one tissue that connects everything together as one holistic system, allowing every aspect of the body to communicate with every other aspect. So extensive, it envelops every minute feature of his anatomy from his brain, spinal cord, muscles, bones, joints, tendons, ligaments, veins and arteries, nerves, organs, and everything else continuously and in multiple layers. 

Being so, it also connects the entirely of the animal together functionally which is one of the reasons why it governs movement and causes his body to behave holistically when responding to posture, coordination, reactivity, reflexes, movement, pressure, loading, impact, friction, etc. Because of this, too, the bones "float" in a tensionally balanced web of fascia, powered by muscle. We know that muscle permits motion by activating the skeleton, but muscle movement would be impossible without fascia to stabilize, guide, shape, and tensionally support it. And fascia doesn't stop on the bone where the muscle does, but communicates to the entire fascia web in different directions, creating a tensional communication system throughout the animal's body. And because every muscle is surrounded by and invested with multilayered and multidirectional sheets of fascia, right down to each muscle fiber, muscle integrity relies almost entirely on the fascia that envelops and holds it together and in place. 

But it doesn't end there—fascia not only creates connection, but also maintains separation so things can slide and squish over each other in response to movement, posture, stretching, and loading. In this way, fascia allows our muscles to move together as groups or separately. Without fascia then, we'd literally be so resistant to movement we would be like the Tin Man! 

But wait—there's more—fascia is also a force transmitter! Force from the muscles, gravity, torsion, and impact are transferred and dispersed primarily through the fascial network. In turn, the fascia prevents or minimizes the stress on a joint, bone, or muscle while harnessing the generated momentum. Subsequently, the fascia net also responds to and distributes forces not just regionally, but as a whole, often withstanding almost three times the strain visited on muscles. And because fascia forms a 3D continuous matrix of structural connection and support throughout the entire body, it also helps the animal to move in multiple directions. Just as muscles move bone, fascia helps to move them both! What's more, myofibroblasts, that allow smooth muscle contractions, are found in fascia as well as mechanoreceptors, both contributing to the smooth muscle–like contractions and communication with the central nervous system about the sheer forces being visited on an area. It's also believed that fascia contraction helps with stability and energy distribution. Gravity also causes fascia to be under constant, passive tension, called resting myfascial tone (RMT), providing stabilization that helps to maintain posture and automatic movements with less fatigue and strain as compared to muscle tension and energy use. 

When fascia is healthy, it's suitably flexible or stiff (where needed), lubricated, and relaxed. Like bone and muscle, fascia will also remodel itself by becoming denser and stiffer along conduits of stress, often consistent with repetitious movement, making the tissue stronger in that regard. This response helps to stabilize and strengthen the body for the particular movements demanded of the animal. However, if injured or under tension, it can bind the muscles and inhibit their motion, causing tension and pressure as great as 2,000 lbs per square inch! In line with that, fascia also influences habitual postures. In other words, bad movement and postures can be "cemented" into place by stiffened fascia whereas good movement and postures can be supported by remodeled fascia. This is because fascia absorbs the imprint of posture or movement, remaking itself to it. Along those lines, injuries are also "remembered" by the fascia which plays a big part in the healing process by "welding" itself in key points to stabilize an area, called "adhesions." However, these adhesions can actually impede movement, and so often need attention with "myofascial release" techniques.

For all these reasons, fascia is both the great unifying connective system of the body and an overriding, powerful biomechanical regulatory system. It's not surprising then that it constitutes the largest percentage of body tissue. Imagine it, if we could magically make everything in the horse's body disappear except for the fascia, we'd see every structure 3D echoed in its fascia support, creating a perfect fascia replica of the animal right down to each capillary and muscle fiber. (The only "blank space" would be for the pupils.) 

What's more, fascia is one of the best sensory organs in the animals' body, with up to ten times more proprioceptors than muscle. Research has even found that fascia may be equal to or better than the retina, which has long been considered to be the best sensory organ. This allows fascia to react far faster than the horse's conscious mind can respond, and sometimes faster than muscle. For this reason, proprioception and kinesthesia (the sense of knowing where our body parts are, how they're moving, and what forces they're experiencing to orchestrate coordination) is more a function of fascia than muscles. Indeed, for every spindle of muscle, there are approximately ten receptors within the surrounding fascia, some of these being:

• Golgi tendon organs: These measure load and fiber stretch.
• Ruffini endings: Alerts the central nervous system to the shear forces on soft tissues.
• Paciniform endings: These measure pressure.
• Interstitial nerve endings: Repeats the information of all the sensors above, plus pain.

Fascia also helps with the elasticity of the body and resilience in motion more than muscle stretches. Indeed, "feeling a stretch" has more to do with the fascia than the muscles. And when the horse stretches, he's stretching the entire fascial web of his body, not just those particular muscles, or in other words, fascia visits onto the entire body what happens on just one area. 

And it doesn't end there! Fascia also responds to emotion and, likewise, emotion travels throughout the fascia web. For example, fascia can become stiffer when the animal is stressed, anxious, fearful, or depressed, reducing the resilience of the entire body system, even causing pain and dysfunction. In contrast, joy, excitement, and being "100% OK" helps to release fascia, inducing more freedom of movement and more supple, athletic motion. 


Fascia also houses the delicate “fly shaker” muscles that shake off files in that characteristic twitchy–skin motion unique to equines while also serving as a heat sink and a means to cushion and reduce friction. It also creates areas of needed stretchiness and expansion like around vessels, veins and arteries, and within the torso and around joints. Furthermore, many portions of the lymph system network within fascia, another important and often ignored feature of anatomy.

And directly related to sculpting, it's fascia that helps to give hide its various textures, character, and surface eccentricities, so we shouldn’t be afraid to input some oddities into the surface of our sculptures to accentuate the appearance of living flesh. Ripples, bumps, pooches, wriggles, squiggles, pock marks, buckling, crinkling, stretches, wrinkles, and other curiosities are typical of the equine head, features that need our attention just as much as hair, musculature, and bone because they add life to our sculpted surface. Absolutely, cranial topography isn’t smooth and polished like sleek metal, but rich with textures indicative of this often–forgotten component of anatomy. 

There's literally no part of the equine body not dictated and affected by fascia—it's an amazing, splendid thing! Yet at the same time, it's perhaps the most universally overlooked tissue in the equine body, and so we have to undertake proactive research to plug that knowledge gap. To start that process, here are some basic kinds of fascia:

• Superficial fascia: Literally everywhere in the body, it helps to facilitate and stabilize the entire body's structures, tensions, and movements. It's like a "body stocking" for the entire physical system.
• Deep fascia: Typically formed of a dense web, it can adapt itself to lines of stress, working much like superficial fascia as well. It also forms the "pods," or fascicles, that create, separate, and form the musculature like a honeycomb web.
• Filmy fascia: A slippery form of fascia that covers the deep fascia, allowing this layer to slide beneath the superficial layer while still being connected to it.
• “Spiderweb”: Acts as a supportive, suspensory network.
• “Bubblewrap”: Serves as a heat sink, reducer of friction, provider of expansion space, and is also a major kind of contouring fascia. Generally, it has air in it or sometimes watery fluid and often oily fluid. For example, there’s a lot of bubblewrap fascia under the scapula and round the point of shoulder to mediate all the friction.
• “Tarp”: Non-stretchy and wraps something such as the aponeurosis of the torso.
• “Gel wrap”: Wrapping in jello-like loose connective wrapping, often serving as a heat sink.
• (Note: Plus the tough Tensor Fascia Latae (TFL) of the hindquarter.)

Now specifically, the head has important fasciæ, as follows:

• Temporal fascia (Fascia temporalis): A deep fascia, it envelopes the Temporalis muscle and attaches to the parietal and frontal ridges and to the zygomatic arches.
• The Buccal fascia (Fascia buccalis): Another deep fascia, it lays over the Buccinator and the ramus. It attaches to the masseteric ridge and posteriorly forms a strap (raphe pterygomandibulare) that runs from the small “hook” of the pterygoid bone to the last molar on the mandible. It blends with and continues with…
• Pharyngeal fascia (Fascia pharyngea): Another deep fascia, it attaches to the thyroid protuberance (cornua) of the Hyoids, the thyroid cartilage of the larynx and the lateral walls and constrictor muscles of the pharynx.
• Superficial Cranial fascia: The head has superficial fascia that creates an almost continuous layer being attached to the skin, though more sparing around the ears, eyes, nostrils, and lips. Embedded within it are delicate thin superficial muscles that help to create the “fly shaker” motion. It blends with the periosteum of the frontal and nasal bones. 
• Cutaneous fasciei: Thin and with an incomplete muscular layer, it sweeps over the mandibular space and the Masseter muscle. One branch runs to the angle of the mouth and blends with the Orbicularis oris. This part becomes the...
• Cutaneous labiorum (also called the Retractor anguli oris): An extension of the Cutaneous fasciei which helps to pull up the angle of the mouth.

While these are main types and locations of fascia, we shouldn't get the idea that fascia ends and begins. Remember it's a continuous, adaptable, and multilayered tissue so the more accurate description would be that it envelops everything as one network, but changes its qualities depending on its function and location.

Overall, fascia is way more than it seems, isn't it? The truth is, it's quite impossible to fully grasp the function, structure, depth, complexity, texture, and nuance of equine anatomy and the nature of the "living moment" without a deep understanding of this marvelous tissue. It could even be said that his entire anatomical story and lifestyle history are told by his fascia, good and bad. Absolutely, to appreciate fascia—to truly understand fascia—is to truly understand equine anatomy. It's the great governor of equine anatomy, yet so often hidden by omission. So make an effort to proactively research fascia, and be prepared to be wowed! It will work miracles with the look of living flesh as well as the subtleties of motion, physics, posture, and expression in our sculptures.

Skin

The skin of the head is thin, delicate, sensitive, and flexible, even thinner around the eye. On certain breeds, such as hot bloods, the skin is especially delicate and thin, known as “dry” since it allows much of the underlaying structures to be easily seen in chiseled relief. The cranial skin is also very soft while the skin of the muzzle is velvety warm and soft, yet quite strong. The lips are wrinkled, as is often the muzzle, and sometimes around the nostrils and often between them, owing to their elasticity. For example, notice the crisscross wrinkles between the Alar cartilages, when seen from the front. There are also delicate wrinkles and buckling around the eye as well as the wrinkling of the brows. Many horses also have a delicate "eye bag" under their lower eye rim. The skin wrinkles around the ears, too, especially on the median side where the bulb meets the crown, or when the ears are bent back, on the backside of the bulb and onto the neck.

Where the tactile facial hairs erupt are “whisker bumps,” or “moles,” soft bulbs of squishy flesh that lend texture to the muzzle and around the eye, especially along the lower rim. When present, the whiskers are long and stiff, providing tactile sensations as a proximity alert for his muzzle and eyes.

The skin on the equine can be pigmented or unpigmented. Pigmented skin is typically a soft charcoal or sometimes dark charcoal brown, or even purple–tinted, blue–tinted, or pink–tinted charcoal or brown depending on coat color. Unpigmented skin is various tones of pink owning to the blood vessels tinting the thin skin. The skin can also be mottled with certain colors or patterns such as with appaloosa, champagne, or grey.

Hair

Equines are thought to have 2,000–3,200 hairs per square inch compared to 1,000 per square inch on our head, 130,000 per square inch on a cat, or 1 million per square inch on sea otters. Hair serves important functions such as insect protection, body temperature maintenance, protection from the elements, insulation of blood vessels and capillaries, sensory stimuli, pheromone production, and it also establishes the many colors and patterns that typify the equine.

That said, the hair on the equine head is fine, often thinning around the eye area and muzzle to expose the skin underneath. Even during winter, the hair on the head with a winter coat maintains its relative fineness. The areas on the muzzle and around the eyes have a distinct velvety texture, something very appealing in life. Sometimes, especially on cold breeds, the hair along the jaw–line grows longer, especially during the winter months. What’s more, often on cold breeds, a “mustache” can develop on the boxy upper lip since the hairs there can grow long and extend sideways. And let’s not forget the prolific whiskers that project from the muzzle and eye area. Inside his ears hair also grows, dense, downy, and soft.

The hair follicle also can vary between breeds. For example, Arabians and other desert breeds have particularly fine hair, especially of the mane and tail. Due to testosterone, stallions can also have a distinct metallic “bloom” to their coats not so pronounced in mares or geldings. Even more extreme, the Teke’s hair shaft is unique, being particularly fine and with distinctive qualities. Specifically, the opaque core of the hair shaft typical of other horse breeds is small, broken up, or absent in the Teke. As a result, the transparent part of the hair, or medulla, comprises the extra space and acts very much like a fiber optic cable being much more translucent, bending light through one side of the hair and refracting it to the other side (as opposed to reflecting in the typical shiny coat), creating that characteristic glow and metallic sheen. It’s believed this is a product of reduced keratin production. What’s more, the Teke hair shafts also possess specific scale patterns, and the smoother and flatter these scales, the brighter the glow. However, not all Tekes possess these coat characteristics while others blindingly so.

Cartilage

Cartilage is a pretty amazing substance. While stiff and able to lend structure, it’s also flexible, resistant to abrasion and friction, and a good buffer for vibration or stress. It’s relatively light–weight, too. This is why it’s often found in joints and those areas that need to flex but still maintain a shape while remaining lightweight. It’s primarily composed of collagen and elastin fibers and is classified into three types, each differing slightly in their make–up with different properties:

• Hyaline cartilage: Hard, quite stiff, and rather translucent.
• Elastic cartilage: Stiff, but more flexible and often found where flexible shape is required by the body.
• Fibrocartilage: A dense fibrous form, making it very tough and with a high tensile strength. In many ways, it’s almost similar to tendon material and tends to be used in stress areas that require very strong, but flexible material.

Like ligaments, cartilage doesn’t contain blood vessels, but is nourished through diffusion, which is why it can be slow to repair if damaged. As for the equine head, it has some key cartilages, as follows:

• Parietal cartilages: A thin, narrow plate of cartilage attached to the free span of the projection of the nasal bone, projecting outwards slightly then curving sharply downwards. Near the nostrils, their “spring” is wider as is their bodies, essentially filling up the space in the naso–maxilllary notch. Its ventral rim is rounded and thick and rests within the groove of the vomer and palatine processes of the premaxillæ. Along with the bony nasal bones, this cartilage forms the noticeable profile and breadth of the nasal area on the head.
• Annular cartilages: Already discussed.
• Comma cartilages: Already discussed.
• Conchal cartilages: Already discussed.
• Scutiform cartilages: Already discussed.

Ligaments

Ligaments are fibrous, inelastic straps that often bind joints together. There are two primary ligaments in the head, those being:

• Lateral ligament: The anterior ligament of the joint of the jaw, attaching the mandible to the maxilla. It’s a strong band that arises from the ventral border of the zygomatic arches behind the eye and attaches to the upper posterior rim of the ramus.
• Caudal ligament: The posterior partner to the former and also a strong band. It arises from the ventral posterior border of the zygomatic arches behind the previous ligament and inserts along the upper posterior rim of the ramus, behind the insertion of the previous ligament.

Detail

The face is rich in detail and it’s these extra touches that can take our sculpted face to the next level of realism. However, we need to always remember scale because out–of–scale details will render a sculpture even more unrealistic than a face without details. For this reason then, we need to adopt media and methods that maintain proper scale at all times. This may even require a different approach to creating details with different scales of work. For example, hinting at moles through adept textural sculpting on a 1:32 miniature scale piece rather than dabbing them on with a brush like we might do for a 1:9 scale piece.

Anyway, for starters, the eyes and muzzle possess long tactile whiskers, each embedded within a “mole,” or whisker bump. They're more profuse around the lower lid than on the upper lid. Since it’s often difficult to add whiskers to our sculptures, the whisker bumps are what we usually recreate. Nevertheless, we could add whiskers by dabbing single hairs into glue or appropriately colored paint and boop them onto the surface of the finished sculpture, then trim them up.

The face also has a profusion of delicate wrinkling, rippling, pock marking, and crinkling, notably around the eyes and muzzle. The lips in particular, can be well–wrinkled, especially the corners of the mouth and between the mouth and the bottom rim of the nostril. And don’t forget between the front rims of the nostrils, or sometimes behind the posterior nostril rim. The face may also have fleshy bumps, “pebbling,” and pock marks, often around the nostril and muzzle. The upper brow is also a rich source of expression owing to its many wrinkles and mobile eye lids. 

Also note the “Y” vein erupting from the end of the teardrop bone and any veins on the ear. And don’t forget fuzzy ears or ear ridges (if the ear is shaved), and that peculiar curl and fold of flesh on the inner ear rim near the bottom "V." Horses have long, overlapping (like a lattice) eyelashes on their upper lid, too, but sparse, fine, small eyelashes on their lower lid. However, the eyelashes aren’t of equal lengths, like an awning, but are longest and most profuse in the middle third, to taper off in the first third and especially the last third of the upper eye lid (sometimes in the latter third, the eyelashes are especially sparse), creating a rounded effect.

Muscle details can really “pop,” too, especially on a “dry” head. In this case, we often see striations or marked hollows, cords, or protrusions, especially with the long, “strappy” types of muscles, especially in the mid–cheek or below and behind the lips and nostrils, or emanating from the chin. We can also see the median groove on the top of the nasal bone, and the swooping line of the nasal bone from the side as it meets with cranial musculature. Behind the chin, where it meets with the end of the bars, we can sometimes see a distinct, abrupt crease, defining the chin even more. The end of the jaw bars project into the chin in a distinct U–shaped crease often giving the chin an abrupt, pinched look from the side. As for the chin, it's often pock marked, wrinkles, and crinkly with soft, velvety texture.

The profile can have bumps or unique, individualistic undulations as can the bars such as tooth bumps on young horses, which may be an important detail for sculpture. On certain breeds, too, muscling can be more robust on the face such as with stock horses who often have beefier jaw and forehead muscling. On the other hand, on other breeds such as the Arabian and Teke, many of the skeletal and muscular details are quite chiseled, or "dry," due to thin facial skin. There’s also a multitude of nerves in the horse’s head. However, the ones most seen on thin–skinned horses are the dorsal and ventral buccal branches of the facial nerve which activates the muzzle, cheeks, eyelids, and ears.

The skulls on different horses can also differ owning to their individual characteristics, especially through the nasal bone profile, the ears and muzzle, the shape of the eyes, and the axis of the skull. The muscles create their own unique effects as well as does fascia and skin. Indeed, facial flesh doesn’t manifest quite the same on any two horses so note any fleshy variations, eccentricities, and textures. There are always differences and it’s these subtle variations that can turn our sculpted faces into individuals, just like our own faces. 

Conclusion To Part 12

Always remember that anatomy charts only tell half the story. There's so much more to the head than just muscles and bone! Factoring in these “lost” features will do much to infuse more believability into our clay, so take note of them during field study and research. They're fun to sculpt, too! It’s very much sculptural playtime when it comes to expressing them since they’re so variable and often textural. We also can't forget how they function when it comes to movement and expression because the effects they produce lend themselves to infusing "life" into our sculpture's face. All the little tweaks, tensions, and relaxations add up!

In the next installment then, we’ll get to the biomechanics of the equine head as well as fascial expression, both are big subjects so get ready to buckle down! Until next time then…smoosh around all these ideas!

“You are an explorer. You understand that every time you go into the studio, you are after something that does not yet exist.” ~ Anna Deavere Smith