It looks easy until you try it. You grab a pencil, sketch a nice oval for the face, and then you realize that drawing a mouth open is actually a structural nightmare that involves anatomy, perspective, and a weird amount of wet-looking textures. Most beginners just draw a black hole with some white chiclet teeth. It looks flat. It looks scary. Honestly, it looks like a cartoon character screaming into the void rather than a human being expressing joy or surprise.
The mouth isn't just a flap on the face. It’s a complex muscle group—the orbicularis oris—wrapped around a curved bone structure. When that mouth opens, everything changes. The jaw drops. The cheeks stretch. The skin around the nose pulls tight. If you don't account for the way the jaw unhinges at the back of the skull, your drawing will never look right.
The Anatomy of the Gape
People forget that the jaw moves on a hinge. It’s called the temporomandibular joint, or TMJ. When you’re drawing a mouth open, you aren't just moving the bottom lip down; you are pivoting the entire mandible. This creates a specific "V" or "U" shape depending on the angle. If you just draw a circle in the middle of a static face, the person looks like they have a hole punched in their head.
Think about the skin. The philtrum—that little dip under your nose—actually flattens out when you open wide. The nasolabial folds (the "smile lines") deepen and move outward. If you’re drawing someone laughing, those lines are deep canyons. If it’s a scream, they might be taut and almost invisible. You’ve got to decide on the emotion before the first stroke.
📖 Related: Creative and Meaningful Will You Be My Maid of Honour Ideas That Actually Feel Personal
And then there's the chin. When the mouth opens, the chin actually moves back and down. It doesn't just go straight down. This is a common mistake in profile views. Look at Andrew Loomis’s classic "Drawing the Head and Hands." He emphasizes the "rhythm" of the face. The rhythm of an open mouth is a downward pull that affects the eyes too. Ever notice how your bottom eyelids pull down slightly when you gasp? You have to draw that.
Teeth Aren't White Squares
Stop drawing individual teeth with dark outlines. Just stop. Unless you want your subject to look like they’re wearing a cheap Halloween grill, you need to treat the teeth as a single mass.
Teeth are translucent. They catch light. They have shadows. In a drawing of a mouth open, the top teeth are usually more visible than the bottom ones. The bottom teeth are often hidden by the lower lip or tucked into the shadow of the oral cavity. Use soft edges. Use a kneaded eraser to "lift" the highlights out of a light gray tone rather than drawing white boxes.
👉 See also: Cracker Barrel Old Country Store Waldorf: What Most People Get Wrong About This Local Staple
The Tongue and the Void
The "black hole" effect happens because people use a flat 6B pencil to fill in the back of the throat. It’s too dark. In reality, the back of the mouth is a fleshy, wet environment. It’s dark, sure, but there’s a tongue sitting in there. The tongue is a massive muscle. It’s rarely flat. It’s usually humped up at the back or pressed against the teeth.
- The Tongue Tip: Usually lighter because it catches the overhead light.
- The Throat: The darkest part, but it should still have a bit of "warmth" or depth.
- Saliva: Tiny, microscopic dots of white can make the mouth look "wet." Be careful, though. Too much and it looks like they have rabies.
Perspective and the "Mouth Bowl"
The mouth is a bowl. If you're looking up at a person with their mouth open, you see the roof of the mouth (the hard palate) and the underside of the top teeth. If you're looking down, you see the tongue and the tops of the bottom teeth.
I’ve seen so many artists draw a front-facing set of teeth on a head that is tilted back. It’s a perspective clash that ruins the whole piece. You have to visualize the dental arch. It’s a horseshoe shape. When the mouth is open, you are seeing into that horseshoe.
✨ Don't miss: Converting 50 Degrees Fahrenheit to Celsius: Why This Number Matters More Than You Think
Look at the work of master draftsmen like Gottfried Helnwein. His depictions of open mouths are visceral and terrifyingly realistic because he understands the tension of the skin. There is tension in the corners—the commissures—of the mouth. They aren't just points; they are fleshy folds where the top and bottom lips meet. When the mouth is wide, these corners stretch thin and move closer to the molars.
Lighting the Interior
Light doesn't just stop at the lips. If a person is standing under a bright sun, that light is going to bounce off their tongue and illuminate the inside of their cheeks. This is "subsurface scattering" in the real world. In a drawing, it’s just subtle shading.
If you're working in charcoal or graphite, use a paper stump to blend the edges of the lips into the interior of the mouth. A hard line between the lip and the "hole" makes it look like a sticker. You want a soft transition. The inner part of the lip is wet mucosa, which reflects more light than the outer, drier skin. This contrast is the secret to making a drawing of a mouth open look three-dimensional.
Common Mistakes to Kill Right Now
- Symmetry: Human faces are weird. One side of the mouth usually opens slightly wider than the other. If you make it perfectly symmetrical, it looks robotic.
- The "Gums" Problem: Don't draw too much of the gums unless the person has a specific "gummy" smile. Overemphasizing the gums makes the drawing look aggressive or skeletal.
- Ignoring the Neck: If the mouth is wide open, the tendons in the neck (the sternocleidomastoid) usually pop out. The skin under the jaw tightens. You can't just draw the mouth and ignore the neck.
Actionable Steps for Your Next Sketch
- Use a Mirror: Don't look at Pinterest. Open your own mouth. See how your jaw moves toward your ears. Feel the tension in your cheeks.
- Map the "Horseshoe": Before drawing teeth, sketch the curved plane they sit on. This ensures your perspective is consistent.
- Tone the Paper: Start with a mid-tone paper. Use white charcoal for the tooth highlights and dark graphite for the depths of the throat. This prevents the "flat" look of white paper.
- Focus on the Corners: Spend more time on the corners of the mouth than the center. The corners define the expression.
- Simplify the Teeth: Group the teeth into one shape. Only define the gaps between the front two or three teeth, and let the rest blur into a single value.
Drawing an open mouth requires moving past the idea of "features" and starting to think about "volumes." Once you stop seeing it as a mouth and start seeing it as a cavernous space with varying textures and light-entry points, your portraits will gain a level of realism that most hobbyists never reach. Focus on the stretch of the skin and the hinge of the jaw. The rest is just shading.