Anatomy of the forehead for injectionists: important nuances of the structure and correction of the zone

Like any other part of the face, the forehead area significantly affects the perception of the face as a whole, and therefore is often the target for injection correction.

A significant factor in determining the safety and effectiveness of aesthetic procedures is understanding the structure of the treated area (location of muscles, blood vessels, nerves, fat pads, etc.) and its aging processes.

Doctors Anna Baker (Anna Baker) and Dalvi Hamza (Dalvi Humzah) in this article estet-portal.com talk about important nuances of the forehead anatomy, which the injection doctor must take into account when correcting with botulinum toxin and fillers.

• How forehead proportions affect the whole face
• Anatomy of the forehead: what layers does the zone consist of
• Features of the structure and location of the frontalis muscle
• What features of the forehead anatomy should be considered when correcting with botulinum toxin
• Forehead artery patterns: important for filler injections
• Recommendations for forehead correction with botulinum toxin
• Recommendations for Forehead Correction with Dermal Fillersand

How do forehead proportions affect the face as a whole

For the purposes of this article, the forehead is considered to be a restricted area:

• bottom – the upper part of the orbital ridge;
• side – temporal ridges;
• top – hairline.

Any change in the height of the forehead entails a change in the proportions of the face.

For example, forehead height may increase due to brow ptosis; this parameter is also affected by the location of the hairline.

Repositioning of the eyebrows due to ptosis increases the horizontal length of the forehead; a low or high hairline also changes its length accordingly.

Fig. 1: skull bones

These factors should be taken into account when evaluating the forehead, especially before performing non-surgical profiloplasty.

In this case, the relative length of the forehead and the angle of inclination of its upper part in relation to the nose and chin are considered.

It is also important to remember that men have flatter eyebrows, while women have – curveds.

Anatomy of the forehead: what layers does the zone consist of

From an anatomical point of view, the forehead can be seen as a structure consisting of 5 layers:

• leather;
• subcutaneous tissue;
• aponeurotic layer;
• loose connective tissue;
• periosteum.

Recent studies have shown the presence of well-defined septa between the periosteum and the frontalis muscle:

• superior frontal septum;
• inferior frontal septum.

They act as points of attachment of the frontalis muscle.

Thanks to this, the frontalis muscle at the lower point of attachment between the eyebrow and the lower frontal septum can perform the function of the levator, and between the lower frontal septum and the upper fibers – line depressorand hair.

Features of the structure and location of the frontalis muscle

Injection of botulinum toxin into points below the lower forehead septum increases the likelihood of eyebrow ptosis.

Often, this septum is located above the upper part of the orbital ridge at a distance of 2-3 cm.

Therefore, it is recommended to inject the toxin over the lower forehead septum.

There are 4 options for the location of the frontalis muscle (Fig. 2).

Fig. 2: frontalis

If you inject botulinum toxin into 5 horizontal points of the frontalis muscle, without taking into account the peculiarities of its location, you can get either an insufficiently pronounced result of the correction, or an excessive consumption of the product.

The lateral extent of the frontalis muscle has not been precisely established.

Considered to be m. frontalis does not extend beyond the temporal crest. However, dissection results suggest that the position of the lateral border in relation to the temporal crest is variable.

Adipose tissue stem cell injections to reverse the signs of facial aging

There is also evidence that the frontalis muscle can overlap up to 2 cm of the circular muscle of the eye from the side of the frontotemporal zone, and the length is m. frontalis up to the musculoaponeurotic junction may be 5 to 9 cm.

The lateral border of the frontalis muscle in 9 out of 49 cases (18.4%) extends beyond the temporal crest.

Fig. 3: the length of the frontalis muscle from the most protruding point of the frontotemporal zone to the musculoaponeurotic junction

Accordingly, the lateral points of injection of botulinum toxin should be located at a distance of at least 2 cm from the most prominent point of the frontotemporal zone (FT) – see Fig. 3.

This will avoid injections of the drug into the orbicular muscle of the eyesa.

What features of the forehead anatomy should be taken into account when correcting with botulinum toxin

Mimic muscles in the upper third of the face are divided into two groups:

• levator brow muscle, which consists of medial, intermediate and lateral fibers of the frontalis muscle;
• muscles that lower the eyebrow, which consist of the proudus muscle, the brow wrinkler, and the orbicularis eye muscle.

There are cases of innervation of the frontalis muscle exclusively by the temporofacial branch of the facial nerve.

Sensory innervation of the forehead is provided by branches of the trigeminal (V cranialrepatic) nerve:  

• ophthalmic;
• mandibular;
• maxillary.

Ocular nerve – the upper point of division of the trigeminal nerve – has three branches:

• lacrimal nerve;
• frontal nerve;
• nasociliary nerve.

The frontal nerve , in turn, is divided into two branches – supratrochlear and supraorbital.

The supratrochlear nerve innervates the medial angle of the eye, the upper eyelid and part of the interbrow.

The supraorbital nerve emerges from the supraorbital foramen and innervates the outer corner of the eye, the upper eyelid, as well as the temporal and fronto-parietal regions of the head.

The supraorbital and supratrochlear arteries run along the respective nerves.

The supraorbital branch emerges from the medial part of the orbital ridge and passes upward to the frontalis muscle.

When evaluating the patient's brow complex, it must be taken into account that an additional hole may be located above the supraorbital.

This feature may increase the risk of eyelid ptosis due to the effect of botulinum toxin on the levator of the upper eyelid.

Brow ptosis due to toxin migration can often be avoided by correct evaluation and selection of patients.

If there are signs of bone aging (flattening in the front of the forehead), it may be advisable to first volume, and then – botulinum therapy.

The injector should work carefully in this area. The doctor must ensure that the botulinum toxin is administered intradermally.

Increased risks when working with this area are known to be due to variability of anastomoses of supratrochlear vessels.

Botulinum toxin allows you to effectively and easily raise the lateral part of the eyebrow.

In order to predict the result of the correction as accurately as possible, a thorough evaluation of the periorbital zone, including:

• degrees of skin laxity;
• degrees of bone tissue resorption;
• strength of the brow wrinkling muscle, the proud muscles and the brow lowering muscle.

Forehead artery patterns: important for filler injections

From the point of view of the anatomy of the forehead, frown lines are also significant: in 50% of cases, the supratrochlear arteries pass exactly under them. 

Vertical lines also have anatomical significance.

Mesial glabellar lines (often referred to by patients as the number 11) can serve as a marker of the supratrochlear arteries in 50% of cases.

Because the deep branches of a. supratrochlearis are absent in 80% of cases, 2 diagrams of the location of the arteries of the forehead:

I – superficial branches of the supratrochlear and supraorbital arteries, deep branch of the supraorbital artery;

II – superficial branches of the supratrochlear and supraorbital arteries, deep branches of the supratrochlear and supraorbital arteries.

Further classification is based on the presence or absence of the central dorsal artery, which runs medially to the superficial branch of the supratrochlear artery.

Fig. 4: diagonal forehead crease This variability should be taken into account when correcting the forehead with

, which should be injected deep using cannula techniques. In some patients, a

is visualized on the forehead, which is associated with a deep branch of the supraorbital artery and marks the border between the medial superficial and lateral temporal fat pads.

tends upward in the lateral direction and exits closer to the surface in three zones between the superficial branches of the supratrochlear, superficial temporal artery and its own branches. Deep branches continue the path of the supraorbital artery superolaterally or divide into medial and deep branches.

and Pessa determined that subcutaneous fat in the forehead area is contained in three superficial compartments delimited by fibrous septa.

Anatomy of the face. Deep fat pads: structural features and correction

et al. in 2017, three superficial (one central and two lateral) and three deep (one central and two lateral) forehead fat pads were identified. The authors also report the presence of longitudinal fibrous junctions that extend from the fascia and cover the posterior part of the frontalis muscle to the periosteum.

In addition, the septa limit the migration of volumizing material from the temporal to the frontal zone.

These results clearly define the

that need to be taken into account for for forehead volume correction. Recommendations for forehead correction with botulinum toxin

Forehead botulinum therapy is advisable to resort to if the target muscle is the main cause of facial harmony disorder.

The literature describes various techniques for injecting and dosing toxin to

by injection into the frontalis muscle. During the examination of the patient's upper face, the doctor should evaluate:

• asymmetry;
• compensation of brow ptosis;
• muscle mass;
• eyebrow width;
• forehead height.
The shape and height of the eyebrow is influenced by the interaction of the frontalis muscle and the medial brow complex.

can be determined by the degree and location of muscle contraction (from 5 to 7 to multipleintrusive points). Recommendations for forehead correction with dermal fillers

The most beneficial for patients with structural changes and deformation of the forehead contour may be

. Many approaches to

have been described in the literature. For example,

– this is a retrograde linear insertion of a high G’ between the periosteum and the frontalis muscle. The entry point may be medial to the temporal crest.

A 38 or 50 mm 25 gauge cannula is used for insertion. This cannula size is recommended for deep insertion and to minimize the risk of vascular damage.

Technique for effectively removing forehead wrinkles Augmentation of the left and right frontal tubercles can be very effective in restoring the upper face in men.

varies depending on the characteristics of the product itself and the degree of correction required.

will be more attractive with soft and prominent bumps all over the forehead. In some cases, it is possible to correct the upper central part of the forehead: the filler is injected

. If necessary, you can work with a filler in the lateral zones of the forehead.

To improve the results of forehead contouring, in particular,

, you can use HA fillers intended for intradermal injection in the blanching technique. A 30-gauge needle is used for insertion, the bevel pointing down.

Small amounts of the product are administered until the wrinkle is reduced or completely smoothed (depending on its depth).

After administration, the treated area is massaged to ensure the integration of the product into the tissues.

New clinical studies shed light on the nuances of the anatomy of the forehead, which are important to consider when injecting correction of this area in order to make procedures safer and more effective.

According to

Aesthetics

.

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