Lip Anatomy

Your lips are two folds of tissue that make up the external structures around your mouth. While you might just be thinking about the softer, hairless skin right around your mouth, your lips actually include a lot more.

The medical term for your lips is “labia oris” or just “labia.” Your upper lip is the labium superior, and your bottom lip is the labium inferior. Here, superior means upper and inferior means bottom (as opposed to better or worse).

What do lips do?

Your lips have several different purposes, including:

• Appearance: Your lips are a key part of how your face looks. That means how you feel about their appearance can affect your overall sense of well-being and ability to feel confident. And lips are something that people may specifically find physically attractive.
• Eating and drinking: Your lips are a part of how you eat and drink. And using them can be so automatic that you don’t even realize how important they are.
• Communication: Your lips are extremely important to your ability to speak. You can also use them for communicating without words. That includes making sounds, facial expressions or even subtle gestures.
• Social interactions: Lips can be part of how you interact socially with others. A common example would be displays of affection like kissing.
• Keeping things out: You can use your lips to keep your mouth closed with an airtight and watertight seal.

What are the parts of the lips’ anatomy?

Your upper lip technically starts at the bottom edge of where your nose extends outward from your face. Your bottom lip ends just as your chin starts to extend forward, about even with where your lower gumline connects to the inside of your lip.

Your lips have the following parts:

• Skin: These are the areas of skin between your mouth and nose and your mouth and chin. They have sweat and oil glands and hair follicles.
• Vermilion: This is what most people mean when they talk about lips. Its name comes from the color it often has, a reddish orange. But your lip color can vary a lot depending on your skin color. It also lacks sweat or oil glands, so it gets its moisture from sources like your saliva.
• Philtrum: This is the small dimple in the center of your face between your upper lip and nose. The philtrum’s lower curved edge, where the vermilion begins, is known as Cupid’s bow.
• Mucosa: This is the part of your lip that extends inside your mouth. It lines the inner mouth walls that rest against your teeth and gums.
• Labial commissures: These are the creases at the corners of your mouth, where your upper and lower lips meet.
• Labiomental groove: This is the small groove or crease between your lower lip and chin.

The main muscles that control your lips are the orbicularis oris muscles. They form an oval under the skin around your mouth. They don’t attach to your skull directly. Instead, they attach to other muscles of your face, especially muscles that attach around your cheekbones and chin.

Your lips also rely on specific nerve connections to your brain. Your facial nerve carries signals that control lip movement. But your trigeminal nerve carries signals to your brain related to your lips’ sense of touch.

What are the common conditions and disorders that can affect my lips?

Your lips are prone to many conditions, ranging from those that are lip-specific to those that affect your skin in general. Possible lip conditions include:

• Injuries, like bruising, swelling or splitting
• Chapping
• Eczema
• Actinic chelitis
• Cold sores (fever blisters) from herpes simplex virus
• Pimples and infected pimples
• Infected hair follicles or ingrown hairs
• Mouth sores (on the inside of your lips), like canker sores
• Cleft lip
• Lip cancer

Common signs or symptoms of lip conditions

Lip conditions often cause changes you can see or feel. They include:

• Color changes
• Pain or discomfort
• Itching
• Swelling or growths
• Changes in lip firmness or texture
• Cracking or peeling
• Dry mouth (for the mucosa area)

Common tests to check lip health

Your dentist is often the main person to help you manage the health of your lips. But your primary care provider may also be able to help, especially with conditions on the lips’ skin area.

Your dentist will usually examine your lips during routine visits like cleanings. A primary care provider is most likely to use a physical exam to check for lip-related skin issues.

Primary care providers can also use lab tests like swab cultures or tissue biopsies. The tests that can help, depending on your symptoms or if they suspect certain issues. Your dentist or primary care provider is the best one to tell you more about possible tests and why they might help.

What are some common treatments for lip conditions?

There are a few treatments that might specifically affect your lips. They include:

• Stitches for some lip injuries
• Topical creams or ointments for specific types of infections or irritation
• Reconstructive surgery for larger injuries or congenital conditions, like a cleft lip

Cosmetic lip procedures

Because lips are such a key part of your facial appearance, there are several types of cosmetic procedures specifically for your lips. Examples include:

• Lip blushing
• Lip augmentation, like with fat transfers or lip fillers
• Lip reduction
• Lip flip

Other types of cosmetic procedures are possible, too. If you have questions about options, your primary care provider can refer you to a specialist who can tell you more.

How can I take care of my lips?

There are several things you can do to help your lips stay healthy and looking their best, including:

• Avoid chapping or treat it quickly.
• Be selective about what you put on your lips.
• Use lip balms that contain sunscreen.
• Stay hydrated.
• Don’t lick, bite, rub or pick at your lips.