The lips are the plump tissues that surround the oral cavity. The ratio between the upper and lower lip, as well as the shape of the lips, vary greatly between individuals and ethnicities. Compared to the rest of the face that could comprise of up to 16 layers of skin, the lips are only covered by approximately three to five thin layers of skin. With an extensive network of blood capillaries and nerve endings, lips are highly sensitive to stimuli. Besides being an important tactile sensory organ and part of the central facial triangle, the lips also play a central role in mastication, speech articulation, expressing nonlinguistic cues, maintaining the oral seal, and outlining the soft tissue boundaries for the teeth. Lips are capable of delivering these functions due to two major structures: the orbicularis oris muscle and the arterial blood supply of the lips.
The former is a major muscle that controls the movement of the lips. It is made of an upper and lower part that are joined to the modiolus. These two parts are further subdivided into two portions called the pars marginalis and the pars peripheralis, which have different locations and functions. While the pars marginalis is located in the vermilion border and functions as a sphincter, the pars peripheralis is found in the cutaneous lip and possesses a dilatory function. The fibers of both the pars marginalis and pars peripheralis originate from the modiolus. However, these fibers are not located on the same plane and actually have different directions. The curved shape of the lips is caused by the location of pars marginalis, which is in front of the pars peripheralis.
The arterial blood supply of the lips is an extensive network of blood vessels, and its lack of melanin pigments contribute to the rosy color of the lips. This network of blood vessels comprises two major arteries, which are the superior labial artery and the inferior labial artery. The former originates from the facial artery and is usually located superiorly, at the same level, or even inferiorly to the labial commissure. With a diameter between 1mm to 1.8mm, the superior labial artery is larger and more tortuous in its course than the inferior artery. The superior labial artery runs into the upper lip and enters the orbicularis oris muscle. It travels between the muscle and the lip mucous membrane, along the upper lip border, and passes deep into the zygomaticus major muscle. On the other hand, the inferior labial artery, which also originates from the facial artery, is usually located below or at the same level as the labial commissure. It is generally smaller than the superior artery, with a mean diameter in its origin of about 1.2mm to 1.4mm. This inferior artery travels indirectly upwards and forward deep to the depressor anguli oris muscle. It then passes through the orbicularis oris muscle and extends indirectly between the muscle and the lip mucosa along the lower lip border.
What are the characteristics of a youthful and attractive pair of lips?
The lips play a huge role in various acts of intimacy; in fact, the shape of woman's lips also visibly indicates her fertility, as the female hormone estrogen, which is associated with fertility helps to sculpt and plump the lips through puberty. A research study revealed that the characteristics of attractive female lips include an increased nasolabial angle, increased vermilion height, and an increased mentolabial angle. A smooth perioral region, which includes the skin above the vermilion border, that is free from any visible rhytids is one of the telltale signs of a youthful lip. Besides that, youthful lips will also have sharply defined philtral columns and a well-sculpted Cupid’s bow that is located centrally. The upper lip should have a prominent medial tubercle with bilateral depressions, while the lower lip should have a centrally-located corresponding small depression and two lateral protrusions. When examined from the lateral view, the upper cutaneous “white” lip should project forward slightly more (about 2mm) than the lower lip. The upper “white” lip should also be short, with a concavity approaching the “red” lip. However, as stated earlier, these characteristics can vary greatly depending on one’s ethnic background. Most youthful Caucasian patients have upper lips that are narrower than the lower lips, with an upper lip to lower lip ratio at approximately 40:60. On the other hand, this ratio is different among patients from the Afro-Caribbean ethnic group, whose own ratio is about 50:50.
What are the characteristics of an ageing pair of lips?
Unfortunately, the aging process brings about a drastic change to the appearance of the lips. The biological aging process that is controlled by one’s genetics causes the usual cell turnover rate to dwindle, resulting in slower cellular growth and rejuvenation. To make matters worse, external aging influences, like smoking, chronic sunlight exposure, and pollution, introduce harmful free radicals into the body. The lips will then succumb to the aging process and display various undesirable signs of aging, which include the following:
- Loss of fullness and projection;
- A reduction in the vermilion border;
- A reduction in vermilion pigmentation;
- A reduction in the nasolabial angle
- Reduction in mentolabial angle;
- Reduction in show of upper teeth;
- Increased show of lower teeth;
- Inversion of lower lip;
- Lengthening of cutaneous upper lip;
- Formation of rhytids;
- Flattening of cupid’s bow;
- Flattening of philtral columns.
A perioral collapse—caused by a combination of fat atrophy, hyperkinetic activity of the orbicularis oris, and resorption of the craniofacial skeleton—usually worsens the aging signs listed above. Lip deflation is not caused by a general loss of volume in the lip. In fact, there is no true volume loss in the lips. Usually, the loss of the pout of the lips is caused by the redistribution of lip thickness along the length. Nevertheless, if the aging signs above are not corrected, patients may end up looking much older than their chronological age.
What is a lip augmentation procedure?
Lip augmentation refers to aesthetic procedures that can help to beautify the appearance of lips by increasing their fullness, sculpting the lip borders, erasing perioral wrinkles, and improving the symmetry between the upper and lower lip. This cosmetic procedure can be done surgically or non-surgically. Nowadays, many patients opt for non-surgical enhancement procedures via dermal filler injections, as results are instantaneous, have short recovery times, and a low risk of potential health complications. That being said, lip augmentation can still be challenging clinically. The success rate of the procedure greatly depends on the chosen injection technique, the type and volume of filler used, and the unique anatomy of patients’ lips. It is imperative that the physicians have a thorough understanding of the lip anatomy and the potential procedural challenges that they will face when undergoing such non-surgical procedures. Most importantly, they should also understand the normal aging process so that they can focus on accentuating patients’ lips and deliver natural-looking aesthetic improvements.
Important considerations of an augmentation procedure
Prior to commencing a lip augmentation procedure, it is important for the medical practitioner at hand to ascertain that patients are healthy and medically fit. Patients with underlying medical conditions like herpes simplex infections must be prescribed with antiviral medication before they are allowed to obtain lip filler injections. Similarly, the treatment session must be postponed if patients are prescribed active herpes simplex infections. The usage of certain medications and supplements that may increase the risk of bruising, such as anticoagulants, analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), and vitamin E, must also be monitored carefully.
Once patients understand the treatment outcomes and potential side effects, physicians can then obtain their written consent to have their lips augmented using soft tissue implants. During the initial consultation session, aestheticians should obtain pre-operative photographs in frontal and lateral views. These photographs can help to determine imperfections and asymmetrical imbalances that should only be corrected once patients agree with the treatment goals. In addition to pre-operative photographs, post-operative photographs must also be taken, as they can be used as a non-biased second opinion in the case where patients return weeks later claiming unsatisfactory treatment outcomes. The pre-procedural discussion session also serves to identify patients’ expectations and ensures that common treatment goals between the patients and physicians are agreed upon. Aestheticians should use laminated photographs of lip dimensions to educate and counsel the patients about the appropriate treatment approach that is best suited to them. Though many patients may request for augmentation of the upper lip only, this approach is unsuitable, as it could lead to a “duck lip” appearance. In fact, research published in The Laryngoscope proposed that a larger upper lip (duck lip) is the most unattractive ratio. That same paper also suggested that facial attractiveness is at its best when the thin and non-treated lips are improved by 53%. Hence, physicians should adhere to these findings and avoid overfilling the lips in patients who request injections of large volumes of filler.
Another consideration to keep in mind is the potential adverse side effects that the patients could face. Patients may be affected with bruising and swelling following the treatment session, with social downtime ranging between two to 10 days. Crucially, they should be made to understand that the side effects may not remain inconspicuous to their partners and/or colleagues. Additionally, a patient alignment checklist is an important assessment tool, as it can help the physicians choose only suitable candidates for a treatment session.
A successful lip augmentation procedure requires the aestheticians to have an extensive knowledge of lip anatomy. The lip function must also be evaluated thoroughly via clinical assessment(s) to ensure that the augmentation procedure is completed without sacrificing any important lip functions. It is best that the physicians accentuate patients’ existing lip architecture instead of overcorrecting the lips. Most importantly, the practitioners should understand the considerations of the procedure and determine the best treatment approaches for their patients.
You may also like: Lip Augmentation Part 2: Best Fillers for Lip Augmentation