What is the Importance of Facial Anatomy and Cosmetic Applications?
In order for interventional procedures performed for both therapeutic and cosmetic purposes to be applied successfully and without complications, it is necessary to know the facial anatomy very well.

Characteristics of the Facial Region
The facial region shows some important differences compared to other parts of the body:

Intense vascularization and anastomoses: It can create both advantages (rapid healing) and disadvantages (risk of embolism) in interventional procedures.

Adhesion of muscles to the skin: Due to the direct connection of mimic muscles to the skin, dynamic wrinkles first occur during mimic movements and then static wrinkles occur over time.

In this article, the basic structures of the facial anatomy will be discussed and the structures that should be considered in cosmetic applications will be emphasized.

Muscle Structures and Clinical Importance
Lip Elevators
Intervention to these muscles can cause drooping of the upper lip and asymmetrical smile. However, in some cases, corrective intervention may be required:

M. Levator alaeque nasi: Attaches to the medial aspect of the upper lip. BTX application should be approached with caution in the treatment of rabbit lines.

M. Levator labii superioris: Starts near the infraorbital foramen and extends to the upper lip.

M. Levator anguli oris: Pulls the lip corner up.

M. Zygomaticus minor and major: Starts from the zygomatic bone and attaches to the lip edges.

M. Risorius: Provides smiling, pulls the lip corner sideways and up.

Lip Sphincter
M. Orbicularis oris: Purses the lips and serves functions such as speaking and whistling. "Barcode" lines form with age. BTX application should be done with a limited dose close to the vermilion line.

Lip Depressors
M. Depressor labii inferioris: Pulls the lower lip down.

M. Depressor anguli oris: Pulls the lip corner down. The muscle should be localized by contracting and a deep injection should be made.

M. Mentalis: Pulls the lower lip forward and up. Jaw roughness is corrected with BTX.

Neck Muscle
Platysma: Starts under the mandible, connects with the lip depressors. Provides neck tone.

SMAS (Superficial Musculoaponeurotic System)
Starting from the platysma muscle, it extends to the galea aponeurotica. It transmits the movement of the facial muscles to the skin. The SMAS layer is targeted in surgical facelift and thread applications.

Vascular Structures
Arteries
Facial Artery: It originates from the external carotid, progresses upwards from the edge of the mandible. It gives off the superior and inferior branches of the labialis A. and reaches the root of the nose as the angular artery. It carries the risk of embolism in filling applications due to its anastomoses.

Superficial Temporal Artery: Passes through the zygomatic arch level, gives off branches to the forehead and scalp. It anastomoses with the ophthalmic artery.

Infraorbital Artery: It is a branch of the maxillary artery. Care should be taken in tear trough fillings.

Mental Artery: Branch of the maxillary artery, originates from the mental foramen.

Ophthalmic Artery Branches (supraorbital, supratrochlear, dorsal nasal): These branches feed the eye area, forehead and nasal dorsum. Care should be taken in filling applications due to anastomoses.

Veins
It runs parallel to the arteries and drains into the jugular vein. Due to the deep connections of the facial vein, there is a risk of cavernous sinus thrombosis in paranasal region infections.

Nerve Structures
Motor Innervation – Facial Nerve (VII. Cranial Nerve)
It originates from the stylomastoid foramen and divides into 5 branches as it passes through the parotid gland:

Temporal Branch: M. orbicularis oculi, m. corrugator, m. procerus

Zygomatic Branch: M. orbicularis oculi, zygomatic muscles

Buccal Branch: M. buccinator, m. orbicularis oris

Marginal Mandibular Branch: Depressor muscles and m. mentalis

Cervical Branch: M. platysma

Temporal and mandibular branches should be carefully protected in cosmetic applications because they are superficial.

Conclusion and Clinical Recommendations
Absolute anatomical knowledge is required in cosmetic applications due to the density and anastomoses of facial artery, vein and nerve structures.

In fillings: Vascular structures and anastomosis areas should be avoided.

In BTX applications: Functional properties of muscles should be considered and involuntary paralysis should be prevented.

In rope applications: Correct planning of the SMAS layer is necessary for a successful result.