December 5, 2022

lip filler augmentation

As healthcare professionals and aesthetic clinicians, our objective with any treatment is to achieve the best results with the least amount of risk, thus it is vital to know and understand the anatomy of the face, and it this case, the specific anatomy of the lip before we use dermal fillers for lip augmentation or restoration.

In this blog, Dr Tim Pearce will share some expert tips on the surface, gross, and histological anatomy of the lip.

This educational piece is based on content from the world’s first online lip training with interactive 3D anatomy and injection animation – introducing the 8D Lip Design training course.

Why is it important to understand lip anatomy?

8D lips - gif1You must be aware of the landmarks around the lips and the relationships between the structures that lie underneath the lips and the visible structures on the surface.

A good knowledge of the reference points (e.g., oral commissures) will enable you to communicate with other aesthetic injectors and your patients, as well as understand learning materials and training updates precisely. Without this, you will flounder, unable to articulate treatment plans to your patients to reassure them or modify your technique intelligently away from a one-size-fits-all template; inevitably you will lack confidence and precision in your technique and thus not achieve the best results possible for your patient, perhaps even encountering more complications.

To really progress as an aesthetic clinician, you must learn the anatomy of the lip which can be broken down into three parts – surface, gross, and histology.

Understanding the surface anatomy of the lip

To understand what controls the shape of the lips, affirms Dr Tim, we must be conscious of all the details that make up a normal, healthy lip.

From a macroscopic perspective, we can see two mobile flaps which meet at rest to form a horizontal slit. The non-vermillion skin of the lip fills a hexagonal shape related to the underlying muscle of the lip, the orbicularis oris. This muscle has its origin in the connective tissue of the midface and insertion lateral to the lip commissure at the modiolus.

The three-dimensional shape of the skin of the lips is a result of the restraints caused by the connections of the muscles and ligaments surrounding the orbicularis oris muscle, the projection caused centrally by the bone and teeth, plus the fatty mucosa which dominates the midline.

The combination of peripheral restraint and central freedom of the lips combined with the projection of the teeth and additional volume of the midline of the lips results in the central projection that we characteristically associate with young, beautiful lips.

On the top lip, the philtrum is the meeting point of two planes. This groove is the final union of three major parts in the embryonic foetus, failure results in a cleft lip and palate. The junction between the vermillion lip and the dermis is the vermillion border, tending to be raised and projected medially and flatter more laterally. The most projected part of the upper lip is usually the Cupid’s bow or central tubercle, which is not always present. Lateral to the central tubercle are two lateral tubercles forming the most voluminous part of the upper lip.

The lower lip is also defined by a dominant, outwardly curled vermillion border that projects out from the mouth, gradually softening as it moves laterally, until it blends almost seamlessly in the lateral third towards the oral commissure, where the top and bottom lips meet. The lower lip tubercles are large and dominant, centrally and create a subtle lower lip angle on the line from the philtrum to the angle of the chin. The oral commissure in the young tends to tilt upwards relative to the trend of the line created by the shadow where the lips meet. With ageing, it tends to tilt downwards.

When injecting the lips with dermal fillers, aesthetic clinicians should aim to preserve, enhance, and respect all the details of the lips, concludes Dr Tim.

You can buy a limited edition beautiful lip anatomy poster for your aesthetic clinic as a helpful reminder of the core structures of the lip.

Understanding the macro anatomy of the lip

The most important structure in the lip is the orbicularis oris muscle. It appears to the untrained eye to be a sphincter-like muscle, but it is not, having two main parts – the pars peripheralis and the pars marginalis.

A full explanation of the orbicularis oris, including the function and pathways of the two parts of the muscle fibres, using 3D modelling is outlined in Dr Tim’s 8D Lip Design training course.

The orbicularis oris muscle is covered by a layer of superficial fascia with connections into the reticular dermis which attach to the muscle through a thin layer of fat into the dermis of the lip peripherally, and more closely at the vermillion border. These connections are the densest on the top lip and are the reason why so many corrugated lines occur here more medially with ageing, notes Dr Tim. Laterally, the connective tissue is less dense and eventually there is no direct connection to the dermis and muscle.

Underneath the muscle is the submucosal layer including the retro orbicularis oris fat pad, which is a vital support to the lip, creating projection, stabilising, and dampening the movement and action of orbicularis oris, and protecting the vessels.

Understanding the arterial anatomy of the lip

There are two reasons why it is key to recognise the arterial anatomy of the lip, one so you can mitigate any risks whilst injecting through better knowledge of the path of core vessels, and two, a deeper understanding will help you to assess and treat the area in the event of a vascular occlusion.

Of course, every patient is different, but you can learn the average anatomy and more common variations as a foundation for your knowledge, going on to learn more through observation, palpation, and perhaps ultrasound imaging if you have access to a device, or choose to seek further training.

The most important arteries in the lip for consideration when delivering dermal filler injections are the labial arteries – the superior labial artery and the inferior labial artery.

The core educational learning relates to the origins of these arteries, relative to other major arteries and landmarks, the depth of the vessels relative to the surface of the skin, particularly relative to the vermillion border, the likely diameter of the arteries, and their common anastomoses or vessels that branch away from the labial arteries which could be vulnerable during such a procedure.

Dr Tim recommends having a read of this comprehensive clinical paper by Souphiyeh Samizadeh et al on Anatomical variations in the course of labial arteries: a literature review.

We do not have time for it in this blog, but Dr Tim covers the origin, depth, diameter, pathways, anastomoses, and common variations of the superior and inferior labial arteries in great detail in his 8D Lip Design training course.

You can also learn how to avoid vascular occlusions by understanding 3D lip anatomy with this great blog from Dr Tim.

Understanding the histology of the lip

lip anatomyFinally, it is essential to appreciate the different tissue types around the lips. They all respond differently to dermal filler, warns Dr Tim, and present important landmarks to guide practitioners as you inject.

Viewing the lip envelope in cross-section, through histology gives you an important perspective on the structures of the lip.

From the histology, we can see an outer layer of skin over a thin layer of fat, the dry mucosa, an inner surface against the teeth – the oral mucosa, the retro orbicularis oris fat pad, and the orbicularis oris muscle as the core structure within. Hair follicles and sweat glands reside in the dermis, salivary glands within the posterior fat pad, and the labial artery within the muscle. For a full breakdown of the histology, including specific skin cell types which change from dry to wet tissue, and vascularisation within each area, join Dr Tim on his 8D Lip Design training course.

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8D Lip Design

With all the conflicting advice out there about lip filler treatments – vertical or horizontal? needle or cannula? – it can be difficult to know how to inject to create the lips your patient desires.

If you are suffering from technique overwhelm, worrying about causing a vascular occlusion (VO), or panicking about injecting thin lips, then Dr Tim Pearce’s brand-new ultimate lip course is going to teach you the different techniques, anatomy, and skills you need to create medically beautiful lips.


Dr Tim Pearce eLearning

Dr Tim Pearce MBChB BSc (Hons) MRCGP founded his eLearning concept in 2016 in order to provide readily accessible BOTOX® and dermal filler online courses for fellow Medical Aesthetics practitioners. His objective was to raise standards within the industry – a principle which remains just as relevant today.

Our exclusive video-led courses are designed to build confidence, knowledge and technique at every stage, working from foundation level to advanced treatments and management of complications.

Thousands of delegates have benefited from the courses and we’re highly rated on Trustpilot. For more information or to discuss which course is right for you, please get in touch with our friendly team.

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