Dr David Jack provides a detailed analysis of the anatomy of the jawline and how to effectively contour this area in male patients using injectables
For many years, the majority of patients visiting my clinic seeking contouring treatments have been female. In the last few years, however, there has been definite upturn in the number of male patients I see – around a 10-15% increase in the last year alone in those primarily seeking filler treatments. Whether this is driven by a greater awareness of such treatments in the press and social media is not entirely certain, however, awareness of the diverse uses of dermal fillers in general does seem to be increasing. For the male patients I see, the most commonly sought treatments are: lip fillers, followed by jawline and chin contouring, followed by mid-face filler.
Given the increased uptake in such treatments, it seems sensible to explore these treatments in a bit more depth. In this article, I will provide an anatomical background for treatments used to contour the male jawline, some background of the differences between the male and female jawlines to consider, and an outline of current treatments that are applicable to this area.
As with any aesthetic treatment, a thorough understanding of the underlying anatomy and anatomy of ageing is paramount to providing the optimum aesthetic result for your patient. A systematic approach to this area, always keeping in mind the underlying normal anatomy, is important to address every issue in a safe and controlled way for the patient seeking treatment.
Establishing the foundation of the jawline, the mandible forms from two halves which are fused in the midline at the mandibular symphysis. Anatomically, it consists of a curved tooth-bearing body, extending from the midline symphysis with the mental protuberance inferiorly (which itself has a central depression and two lateral mental tubercles, forming the chin), to the ramus laterally.
The ramus projects superiorly with two processes: the coronoid process, to which the temporal muscle attaches, and the neck and condyle process, which is topped by the articular surface, forming the mandibular part of the temporomandibular joint. Between these two processes of the ramus is the mandibular notch. The large masseter muscle attaches to almost the entire surface of the ramus of the mandible, and is the major component of the fleshy part of the lateral jawline, which can be palpated on examination. This tends to decrease in bulk with age.
The body of the mandible also provides origin or attachment for several muscles: the mentalis and part of the orbicularis oris originate from the incisive fossa, just inferior to the incisor teeth; the depressor anguli oris and depressor labii inferioris attach to the oblique line superiorly and the platysma muscle attaches inferior to the line.1 There are two important foraminae, one each side, transmitting the inferior alveolar branches of the mandibular branch of the trigeminal nerve. The nerve enters the mandible via the mandibular foramen in the ramus of the mandible, behind the deep surface of the lateral pterygoid muscle to the deep surface of the masseter.
The large masseter muscle attaches to almost the entire surface of the ramus of the mandible, and is the major component of the fleshy part of the lateral jawline, which can be palpated on examination
Within the body of the mandible, the nerve runs in the mandibular canal and gives off branches supplying sensation to the teeth, then exits the bone as the mental nerve with the mental blood vessels via the mental foramen to supply sensation to the chin and lower lip.2 The mental foramen is located lateral to the mental tubercles and changes direction from childhood as anterior facing to posterosuperior in adulthood. The location and direction of these nerves are important to consider when selecting which injection technique to use (cannula or needle), to minimise risk of damage.2
The superficial fat pads and salivary glands of the face are another important consideration in this area when it comes to injectables. Superficial to the ramus of the mandible and masseter, the parotid gland varies in size between individuals and can extend posteriorly to the deep surface of the ramus. It contains the parotid duct, which pierces the buccinator muscle to open into the vestibule of the mouth at the level of the second maxillary molar. The gland also contains the trunk and main branches of the facial nerve.
Superficial to the gland is superficial lamina of the deep cervical fascia, and posteriorly, the greater auricular nerve is in close proximity. The lateral temporal cheek fat pad lies superficial to the parotid gland, with the middle cheek fat pad compartment anteriorly, and the superior and inferior jowl (or mandibular) fat pads lying further anteriorly over the anterolateral surface of the body of the mandible.3 These fat pads are separated by a number of important septae or ligaments that give rise to some of the characteristic signs of ageing seen in the lower face. These include the mandibular septum, which separates the jowl fat pads from the neck fat and is adherent to the anterior surface of the body of the mandible,4 and the mandibular cutaneous ligament, which tethers the skin anterior to the jowl fat pads to the bone anteriorly, creating the groove seen anterior to the jowl with descent of the fat pads in age.5,7
Developmentally, all faces start phenotypically as female, then under the influence of significantly elevated testosterone levels during puberty in the male, secondary male characteristics develop
Running over the superficial surface of the mandible in the plane deep to the platysma, risorius and zygomaticus major, the facial artery branch of the external carotid lies relatively superficially, being crossed superficially by branches of the facial nerve, deep also to the superficial fat pads of the face to run superomedially in a tortuous route over the face. The point at which it crosses the border of the mandible can be easily palpated and should always be noted and marked with any injectable treatment to avoid damage or intra-arterial injection.
The marginal mandibular branch of the facial nerve is another important structure to be aware of when injecting in this area. Running deep to the platysma and the depressor anguli oris, it crosses the border of the mandible from the neck about 3cm anterior to the angle of the mandible, always superficial to the facial artery and anterior facial vein,3 and provides motor supply to the depressor labii inferioris, depressor anguli oris and mentalis, and communicates with the inferior alveolar nerve.3,7
Developmentally, all faces start phenotypically as female, then under the influence of significantly elevated testosterone levels during puberty in the male, secondary male characteristics develop.6 In the jawline, these features include a much larger, stronger and heavier-set jawline, more definition of the angle and ramus of the mandible, and higher muscle bulk generally. The male chin tends to be wider and more square, rather than V-shaped in the female. It is exceptionally important to consider the individual patient when assessing for contouring treatments, and to have a different approach in male patients than you would for females, to avoid feminisation of these features.6
A number of changes appear with ageing in the lower face in both men and women, including: loss of volume and descent of the jowl fat pads (in addition to reduction in mid-face volume and descent of the mid-face structures), dehiscence of the mandibular septum and descent of mandibular fat pads into the neck, mandibular bone resorption (particularly with loss of dentition in later life) and increased skin laxity. Gravity and the downward pull of the strong platysma muscle accelerates this volume loss-related descent.
Jawline enhancement and contouring is a treatment that can make quite a significant difference to the entire face, for both men and women
Treatments in this area can be targeted for two distinct purposes – firstly, to address any anatomical deficit that may be present, which can be augmented in a way to provide a more harmonious masculine jawline in relation to the other facial structures – i.e. adding volume that was never there in the first place.
Secondly, to address signs of general ageing in the jawline, by replacing volume that has been lost over time. Jawline enhancement and contouring is a treatment that can make quite a significant difference to the entire face, for both men and women. In women, contouring techniques using injectables tend to be used primarily to create more of an almond-shaped face.6,8 In men, most often these techniques are used to create a more defined, masculine appearance, improving the definition of the angle of the mandible and creating more of a rectangular, strong chin.
As mentioned above, any technique in the lower face should be considered to both replace what has been lost with age, and to augment and add volume to where volume has never been in the first place. The use of any injectable in this area is therefore based on the injector’s own perception of the volumetric three-dimensional starting point of the individual patient. There are numerous lines of projection that can be used as a guide for chin projection – such as an ideal chin being one that reaches a continuous imaginary line in the sagittal plane, drawn from the menton, to the most anteriorly projecting part of the lip.9 Likewise, a photogrammetric study conducted in 2016 found that the ideal male jawline had the following characteristics:10
As with any aesthetic procedure, appropriate patient selection and management of expectations are probably the key factors in determining success. It is likely, from my experience, that men seeking jawline contouring treatments are generally those for whom body image is particularly important. A thorough history, including screening questions for any symptoms of body dysmorphia is essential, and a thorough explanation of the limits of the particular treatments being undertaken is of course mandatory.
For dermal filler treatments in the jawline, it should always be mentioned to patients that there will be a possibility of need for correction with further filler at a later stage to refine the result. It should also be explained that a gradual approach is necessary, that there are limitations to the ability to correct any perceived underlying asymmetry and that no desired aesthetic outcome can be necessarily guaranteed. Likewise, with any radiofrequency or HIFU treatment being used to improve jawline contour, it must be emphasised that the results from such procedures are subtle and again, no particular outcome can be guaranteed.
With the ideal proportions and angles in mind, and the ideals of the male face set out, it can be quite a challenge to decide exactly which techniques and products are going to be best for our individual patients. As with all areas of the face, I find a combination treatment approach is always best; combining injectables with skin surface treatments. I find it useful to keep in mind whether I am primarily replacing or primarily augmenting volume, which always helps with the estimation of how much product might be required. Usually, I find that less is needed for primarily augmenting volume in younger patients.
For male jawlines, I normally select a filler with a relatively high G-prime (i.e. high elasticity and viscosity), as the filler is likely to be subject to a number of deforming forces during its lifetime, particularly if injected in the masseteric area. My filler of choice for deep contouring would be Juvéderm Voluma, given its reversibility and high G-prime. Others, such as Restylane Lyft and Teosyal RHA 4 are also good choices. I personally rarely use collagen-stimulating fillers due to their lack of reversibility in the event of a vascular compromise.
Injection techniques are very much dependent on personal preference, but a combination of needles and cannula techniques are often required for this area, particularly around the facial artery, where a cannula is often preferred by some injectors. Likewise, a gradual augmentation is often desirable, so spacing treatments over a number of sessions is a good idea to avoid overfilling.
I normally select a filler with a relatively high G-prime, as the filler is likely to be subject to a number of deforming forces during its lifetime, particularly if injected in the masseteric area
Although every patient is different and it is impossible to give a general rule about male jawline contouring, my technique usually involves deep intramuscular boluses of filler onto the periosteum in the region of the angle of the mandible using a needle. Usually, if using two syringes of 1ml, this would be around 0.3-0.5ml on each side in two to three points. I generally then use a bolus of around 0.1-0.2ml bilaterally, just anterior to the mandibular retaining ligament, to correct any slight defect there, should there be any. Again, this is a deep injection.
Then, I would place a deep bolus onto the surface of the mental process on each side – 0.1-0.2ml – to square the chin if need be. It is sometimes advantageous to use a little bit of filler slightly more superficially in the subcutaneous plane using a cannula along the area of the body of the mandible, however, the need for this varies from patient to patient. It is a high-risk zone, due to the presence of the marginal mandibular branch of the facial nerve and the facial vessels, so should only be attempted by experienced injectors and where there is definite need. Neurotoxins can be used in this area too, particularly if there is some drooping of the jowl fat pads. I approach this by asking the patient to grimace, then when the platysma is fully activated and contracted, I mark the bands – the strongest of which tend to be those posterior to the mandibular retaining ligament.
I then inject along the bands, making sure the most superior injection point is at least 1cm below the jawline to avoid any inadvertent spread and relaxation of the depressors of the mouth. I tend to find around 20-25U of botulinum toxin sufficient in this area – this is of course an off-label use of toxin products. Likewise, a small dose of toxin injected into the mentalis can also improve the chin area. Skin and SMAS laxity in older male patients is also an important consideration, so energy-based treatments such as HIFU and radiofrequency (both ablative and non-ablative) can often be useful adjunctive treatments to injectables in this area, usually also treating the mid-face.
The jawline is an area that is of concern to many male patients seeking aesthetic procedures. A comprehensive knowledge of the anatomy is important when considering treatments in this area, so in this article I have outlined the most important structures to consider when it comes to injecting here. As with other areas of the face, it is important not to treat in isolation and ideally use a number of different treatment modalities for an optimum result.