Lips | Definition, Anatomy, Synonyms & Antonyms


Lips are the part of our face. They are the external and visible parts of our mouth. They play a significant role in facial expression, phonation, feeling, mastication, physical attraction, and familiarity. These are made up of surface epidermis and connective tissues. In Latin, it is known as Labia oris.

Definition of Lips

They are the two plumpy parts that form the upper and lower edges of the opening of the mouth and encircle the hole of the mouth.

They are made up of integument externally and of mucous membrane internally among which are found the Orbicularis oris muscle, several nerves, areolar tissue, fat, labial vessels,  and several small labial glands.

Etymology of Lips

This word originates from Old English lipp of Germanic origin related to the Dutch lip and German Lippe from an Indo-European root shared by Latin labia, labra lips.


  • Edge
  • Rim
  • Brim
  • Margin
  • Border
  • Verge
  • Brink
  • Boundary
  • Perimeter
  • Mouth


  • Center
  • Within
  • Core
  • Inner
  • Interior
  • Middle
  • Politeness


They work to close our mouths and to keep food and drink inside. Also, it helps to hold food among the upper and lower teeth during chewing.

They push food into the oral cavity properly during the intended phase of swallowing where it is ingested and prepared for digestion in the stomach and in the small intestine. Some of its main functions are:

  • Food Intake
  • Articulation
  • Tactile Organ
  • Erogenous Zone
  • Facial Expression

Anatomy of Lips

Upper Lip:

It is also known as Labium superius Oris. It covers the frontal surface of the body of the maxilla. The skin color of its upper half is normal. This has a depression at its middle which is beneath the nasal septum which is Latin for lower nose.

While it’s lower half has a noticeably different and red-colored skin tone similar to the color of the inside of the mouth and the word vermillion refers to the colored part of either the upper or lower lip.

Lower Lip:

It is also known as Labium Inferius Oris. It is made from the mandibular prominence which is a branch of the first pharyngeal arc.

This part of the lip covers the anterior body of the mandible. It is lessened by the depressor labii inferioris muscle and the orbicularis oris.

Types of Lips

There are many types of lips some of these are:

  • Full Lips: This type of lip is so common. They are completely proportionate with balanced upper and lower lips which appear fleshy.
  • Wide Lip: These types of lips are generally longer as they are full and reach from cheek to cheek to make the smile unique.
  • Narrow/Thin Lips: This shape of the lip is a natural physical feature where the upper or lower lip is smaller in breadth as compared to normal.
  • It can be heritable or also because of aging as the production of collagen decreases which causes the lip to lose volume. This type of lip is normal and healthy.
  • Heavy Upper Lips: In this type of lips, the upper lip is heavier larger, or fuller than the lower lips.
  • Down-Turned lips: This shape is recognized easily because, in this shape of lip, the face is a little downward at the edges. It gives a natural slight pout to the mouth.
  • Heart-Shaped Lips: This type of lip is shaped like a prominent V-shaped cupid’s bow. In this shape, a person has a dip in the center of the upper lip and may also have a heavier lower lip.
  • Bow-Shaped Lips: It is one of the rare shapes of the lips. This type of lip is full in size with an upper lip. It looks like a bow such as a cupid bow and arrow.
  • Round Lips: In this shape, the lips are at an equal distance from both sideways and lengthways. They create an O. They can be smaller or larger but they always have a full circular look that makes them unique.
  • Heavy Lower Lips: In this type of lip, the lower lip is heavier larger, or fuller than the upper lips.


The layers from superficial to deep include:

  • Epidermis
  • Subcutaneous Tissue
  • Orbocularis Oris Muscle Fibers
  • Mucosa

Nerve Supply

Infraorbital Nerve:

It is a branch of the maxillary branch. It supplies not only the upper lip but also a lot of the skin of the face among the upper lip and the lower eyelid apart from the bridge of the nose.

Mental Nerve:

It is a branch of the mandibular branch. It supplies the skin and mucous membrane of the bottom lip. Also, to the labial gingival anteriorly.


The muscles are considered a part of the muscles of facial expression of the lips. They are managed in groups which are:

  • Buccinator
  • Orbicularis Oris

Anchor point for Numerous Muscles:

  • Modiolus

Lip Elevation:

  • Levator Labii Superioris
  • levator Labii Superioris Alaeque Nasi
  • Levator Anguli Oris
  • Zygomaticus Minor
  • Zygomaticus Major

Lip Depression:

  • Risorius
  • Depressor Anguli Oris
  • Depressor Labii Inferioris
  • Mentalis

What are the Lips made up of?

They are soft flexible anatomical structures. It forms the mouth margin of most vertebrates which is comprised of of a surface epidermis, connective tissue, and a muscle layer. The external skin comprises hair, sweat, and sebaceous glands in man.

15 Zones of the Lips

  • Upper Lip
  • Philtral Zone
  • Vermillion Central Zone
  • Vermillion Cupids Apex Zone
  • Vermillion Lateral Zone
  • Subvermillion Medial Zone
  • Subvermillion Lateral Zone
  • Peristomal Medial Zone
  • Peristomal Lateral Zone
  • Under Lip
  • Commissural Zone
  • Peristamal Medial Zone
  • Peristamal Lateral Zone
  • Subvermillion Medial Zone
  • Subvermillion Lateral Zone
  • Vermillion Medial Zone
  • Vermillion Lateral Zone

Lip App

YouCam Makeup is the best lip-shaper app. It changes the shape of the lip in photos including receiving a lip peak, changing lip breadth, and plumping the lips. The shape of lip shape can be edited naturally and accurately with an easy swipe on the slider with the help of advanced and modern AI technology.

Uses of Lips

There are many uses for lips in some of these are:

  • Eating Functions
  • To hold food & drink inside
  • It works to close the mouth airtight shut
  • It keeps out unwanted objects
  • It helps us in chewing and swallowing
  • It is used in conversation or communication
  • It permits us to smile

Lip Disorders

  • Cheilitis
  • Erythema Multiforme
  • Cold Sore
  • Lichen Planus
  • Squamous Cell Carcinoma
  • Acanthosis Nigricans
  • Cleft Lip
  • Labial Pits
  • Psoriasis
  • Actinic Keratosis
  • Erythroplakia
  • Systemic Lupus Erythematosus
  • Primary Syphilis
  • Fissured Tongue
  • Aphthous Ulcer


  • Saba’s lips began to tremble.
  • Ahmad bit his lower lips.
  • Ali licked his lips.
  • She has pink lips.

FAQs (Frequently Asked Questions)

Mention the full form of the lip.

The full form of the lip is Lymphocytic Interstitial Pneumonia (LIP).

Which type of organ is the lip?

It is a somato-sensory organ.

How can I draw lips in my notebook?

  • Draw a vertical line
  • Refine the outline
  • Show the volume in the lower lip with two ovals
  • Add a shadow of the upper and lower lip with a pencil
  • Add some shading
  • Tone to the whole drawing
  • Add the lines on the lip
  • Give the final touch

Mention the names of the 4 important types of lips.

  • Heart Shaped
  • Round
  • Full
  • Thin

Why are lips useful?

They are useful because they play a significant role in:

  • Facial expressions
  • Phonation
  • Sensation
  • Mastication
  • Physical Attraction
  • Intimacy
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