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Department of Medicine, College of Medicine and Health Sciences, Al Ain, United Arab Emirates
The lower third of the face is its most dynamic part. It encompasses soft structures such as the lips , as well as bony ones such as the angle of the jaw and a mix of the two such as the chin . In humans, that part is responsible for verbalization and speech, in eating, in performing certain sexual functions such as kissing and may be of importance depending on the person’s profession, as in the case of musicians. In addition, parts of the lower face can portray masculinity or femininity; a strong jawline with squared chin or full rounded lips , respectively.
Unlike the upper, where neuromodulator use is key and is an essential part of facial rejuvenation, the use of that in the lower can potentially lead to major adverse events when injected inappropriately. Areas where botulinum toxin may be injected in the lower face are the lips when injecting the orbicularis oris , the softening of the marionette lines when injecting the depressor anguli oris , softening of the chin by injecting the mentalis and finally, decreasing the roundness of the face or in cases of bruxism in those patients with strong masseters . Thus, the lower third has always relied more on the use of fillers for augmentation and to reverse the signs of aging.
Blood vessels in the lower third run deep and injection of fillers is generally performed more superficially. Branches of the facial artery run in the deeper plane, with the only superficial part of that the artery running along the mandible and palpable right anterior to the masseter muscle. Neurovascular compromise in the area is highly unlikely, given that the artery is quite large, but it can readily occur in its branches, such as the superior and inferior labial arteries . Another major vessel of the lower face is the mentalis artery, which comes off from the mental foramen. Though large, the vessel may be compromised and embolism may lead to necrosis of the parts of the chin . That being said, bruising is much more common in that area than neurovascular compromise. This owes to the high dynamism of the area where there are many arterial branches, venous tributaries and capillaries present.
Lips
The lips are perhaps the most important structure of the lower face. They have many uses and functions. Lips are also an extremely popular indication for filler injection for volume restoration and augmentation. The procedure has increased in popularity recently due to the effect of media with the younger population. Depending on who you ask, the lips and to a slightly lesser extent, the tear troughs , are the most popular area of injection across the board when it comes to filler injections, especially amongst the youth. This is especially true given that major studies performed find that men are attracted to women with fuller lips . This is attributed to the notion that people with fuller lips have higher estrogen levels and thus are seen to be more fertile. This has not only been true in the field soft tissue augmentation, but also in cosmetic products available in the market produced for that part of the face.
When seeing and assessing the lips during the consultation process, it is important to understand two things: the shape of the upper lip and the volume of the lower. The upper lips should retain its shape and augmentation in that area should always respect that aspect and add more to it. Increasing the upper lip volume can lead to unnatural results and is more apparent when compared to changes of volume in the lower lip , where that is expected. In addition to this, the upper lip is slightly smaller than the lower. The change may be highly visible in different ethnicities such as Caucasians, where the difference in ratio can be up to 1:2. That, however, is not the case in people of African origin where the upper and lower lips have equal ratios. The lower lip provides the bulk of the volume. Though that being said, there are volume differences across the lip itself, with maximum volume occurring lateral to a depressed midpoint, giving off a shape similar to that of a dumbbell. In addition, the upper and lower lips lock onto each other like a key and lock frame. The central part of the upper lip fitting in nicely in the lower’s midline depression. During the process of augmentation, the upper and lower lips should both be treated, even though one may need slightly more modification than the other. Failure to do that can make the lips appear unnatural. If artistry is ever looked into the soft tissue augmentation, the lips are the most important part of that assessment.
The lips are identified as having both a cutaneous, or hair bearing, component and a mucosal component. The vermilion border separates the components apart. Interestingly, when fillers are injected in the vermillion border, it is possible to see filler move into the vermillion in an area further away from the point of injection as if the filler was being injected in a tunnel or passageway. Stiffer fillers, especially those that are biphasic will do such a thing more readily than the softer monophasic type. That being said, there is no discrete anatomical structure in that area that does not allow the filler to move upwards or downwards. Other parts of the lips include the oral commissures , or the angles of the mouth. The commissures tend to change with time as the angle moves from an upward slant to a more horizontal to finally ending up in a more downward slant and continuing as part of the marionette lines that separate the chin and cutaneous lips from the cheeks . The Glogau-Klein point of the upper lip is the point of maximum deflection between the cutaneous and mucosal parts. This point is essentially part of the vermilion. The central part of the upper lip has a specific shape as the vermilion changes its angle from an upper to slightly lower. That point usually coincides to a vertical line or philtral ridge that goes up to the lateral side of the columella of the nose. The central part, where the vermilion border of one side meets the other, is known as the philtrum , which is an outward protrusion of the upper lip and its area of maximum projection. This philtrum sits on top of the lower lip ’s central depression. This whole structure of the upper lip is commonly called the cupid’s bow given its shape.
Anatomically, the major vessels supplying the lips are the labial arteries , the superior and inferior. Both are branches of the tortuous facial artery as it goes up the cheeks towards the middle third of the face and nose . The arteries run deep but may be compromised if an injection into that area causes embolization. This is uncommon, but can happen and should be identified appropriately and in a timely manner to avoid scarring. Bruising is much more common and is caused by damage to the veins. Bruising may be extensive owing to the mobile structure of the lips and can at times be seen in the mucosal part of the lips too.
Procedure (Upper Lip ):
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- 1.
Choose the right filler. The only filler that should be injected in the lips is a hyaluronic acid . Lumps and bumps may occur and fillers that may not be dissolved should be avoided.
- 2.
Stiffer fillers may be used to inject the vermilion border , but should generally be avoided in volume replacement as they may be felt. Highly cohesive fillers that are soft are the materials of choice for volume enhancement
- 3.
Needles (30 G or smaller) and cannulas (27 G) may be utilized in the augmentation process.
- 4.
The oral commissures and the angle of the mouth are the first areas to be treated.
- 5.
Injection is performed at a point 5 mm lateral to the oral commissures .
- 6.
The needle is inserted straight to the angle and a small amount of filler is injected.
- 7.
The needle is advanced to the lower lip and a small amount is injected in the area of the vermilion.
- 8.
A much smaller amount is injected in the upper vermilion to produce what looks like a “C” shaped structure.
- 9.
There will be an immediate visible lifting of the angle of the mouth.
- 10.
Further support of the angle may be achieved by injecting perpendicular to the filler lateral vermilion towards the lower lips . This buttresses the filler in the area.
- 11.
The upper lip is treated by injecting the vermilion 0.5–1 cm medial the oral commissures . If the whole vermilion is enhanced with filler, the upper lips may appear longer similar to that of a duck’s bill. This is quite unnatural and is a sign of poor technique.
- 12.
When injecting the vermilion, one may see the filler moving across it and the subsequent injection will be slightly more lateral. Given that most HA filler contain lidocaine , that area will be numb when the needle is introduced.
