- The scutiform cartilage: A small plate of triangular–shaped cartilage on the temporal muscle that acts as a fixed point and stabilizer for some of the ear’s muscle attachments.
- The outer ear: The conchal cartilage (or auricular cartilage), the delicately curved flute of cartilage responsible for the visible shape of the ear. Attached to the external acoustic process of the petrous temporal bone, the base of the concha is a rounded bulb (Eminentia conchæ), almost globe–like in structure, and rests nestled in a pad of fat (Corpus adiposum auriculæ), making the movements of the ear like a ball–and–socket joint. The long tube–like aspect of the conchal cartilage is called the pinna (or auricula) (plural: pinæ) which projects from the bulb in an upright fashion. Its convex surface (or dorsum) faces backwards (when the ear is facing forwards) and is widest in the middle aspect while its upper portion (apex) flattens out and narrows to a rounded point, which can have various degrees of medial or medial posterior curvature depending on breed type or individual variation. The pinna itself is rather flexible, becoming more so towards the apex while the bulb is more rigid. The outer rim (or posterior border) runs uninterrupted from the “V” to the apex, and is straighter and flatter than the inner rim (anterior border) which is delicately and deeply curved to meet its partner in the “V.” It’s concave at the apex and convex as it approaches the “V.” This inner rim divides into two subtle parts next to this “V,” forming an overlapping fold and concave twist towards and within the “V” (a detail often missed by sculptors). This configuration changes shape as the ear is moved. Inside the ear, under the fuzzy hair, exist several delicate ridges radiating outward which soften and disappear towards the apex and outer rim. When the ear is pricked forwards, the “V” opening at the anterior base faces forwards, but when the ear is twirled backwards, this “V” faces backwards and downwards. Its movements are orchestrated by multiple muscles that actively move those mobile ears in various ways to home in on sound or create expressions for communication. The ligaments of the ear are more elastic while the bulb at the base serves as an attachment for most of the ear muscles, and the parotid gland overlaps the bulb on its lateral aspect. Below the bulb, the conchal cartilage narrows to form a curved tube which is covered by muscles and bordered by the parotid gland below. Its lowest aspect has a pointed, curved projection called the styloid process which is about 1” long (2.5cm) and projects over and covers the…
- The annual cartilage: A small, plate–like ring of cartilage surrounding the auditory process of the petrous temporal bone of the skull that helps to connect the conchal cartilage to the bone. Its surface is somewhat convex from side to side while its inner surface is similarly concave. Its front part is rounded and thin while its back aspect is wider and thicker, with a pointed process along its medial rim that’s about .50” (or more) long (1.2cm). This cartilage moves freely.
- The external auditory canal: A short bony tube projecting from the petrous temporal bone.
- The middle ear: Entails the malleus, incus, and ossicles (also known as the stapes bones), eardrum cavity, and the Eustachian Tube. Basically it contains the eardrum which transfers sound waves into the inner ear for the brain to process.
- The inner ear: Fluid–filled, it’s located within the petrous temporal bone and contains the fleshy and bony canals (also referred to as “labyrinths”) and the cochlea. It translates sound waves into impulses the brain can understand. It’s also important for balance control.
- Hair: In its natural state, a thick proliferation of soft, downy, fuzzy hair grows within the pinea to protect the inner ear from debris and insects. However, for show, this hair is often shaved to reveal the subtle ridges on the ear’s inner surface, radiating from the ear hole somewhat like spokes on a wagon wheel.
That said, he exploits two ways to localize sound sources. The first is the time delay the sound signal arrives at each ear, revealing which ear is closest to the source. That is to say it takes slightly longer for a sound to reach one ear than it takes to reach the other ear. So if the source is directly in front of or behind the head, the sound arrives at both ears simultaneously. However, if the source is off to the side, one ear receives the sound waves slightly sooner than the other ear. As for the second way, the head casts a "sound shadow," so one ear hears a sound slightly louder than the other, indicating the direction of that sound. For this reason, animals will a larger spaces between the ears—wider crowns—may have better sound localization abilities, another benefit of a larger head.
Curious though, less distance between the ears can usually cause an animal to detect higher frequencies better. The distance between the ears in horses, as measured from one ear canal to the other, is about 7" (18cm) compared to about 11–12" (28–30cm) in people. Because of this in part, horses have a greater sensitivity to high–frequency sounds, however, equines aren't that good at localizing them. This is why a horse may hear a whistle, but not be so good at discerning where that whistle is coming. However, equines have such sophisticated vision and scent abilities for predator detection, they don't really need to pinpoint the exact location of a sound, only the general direction to run away from it.
Nonetheless, equine ears are no easy thing to sculpt. Their convoluted shape, nuanced details, expressiveness, mobility, location and "seat," and changing nature will always challenge us no matter how experienced we become. In fact, if we're truly doing our job, we'll pay very close attention to them, just as much as sculpting an eye or nostril. Indeed, incorrectly or carelessly done ears can destroy our illusion just as quickly as anything else. Yet too many artists only give the ears a cursory treatment, seeming only to settle for approximating their qualities with oversimplified treatment. Still others don't quite understand them and so create errors in shape, symmetry, movement, details, or placement. For these reasons, we can deduce a great deal about an artist's abilities by inspecting their sculpture's ears. Any misinterpretations or stylizations there will reliably indicate errors elsewhere on the sculpture.