Facial Anatomy

Facial Anatomy

When considering the anatomy of the face for rejuvenation with injectable treatments it is very helpful to think of it in its entirety as a three-dimensional structure that consists of five unique layers running superficial to deep. This is important so that we know which structures we are aiming to treat & the success we will gain from each approach.

We must remember, that the ageing process effects not only the most visible part of our face, the skin, but also other intrinsic factors that are at play including deep fat layer loss as well as loss of muscle laxity & ligament and bone deterioration dramatically accelerate ageing.

The first layer, the outer most layer of the face is the skin, comprises of both the epidermis and dermis. Beneath this you will find the subcutaneous layer that comprises of fatty tissue. The subcutaneous layer sits on top of the fascial layer that varies depending on the area of the face. For example, in the forehead the fascial layer contains the frontalis muscle, the temporal region contains the temporal parietal fascia and below the zygoma in the mid and lower, the fascia becomes the SMAS (superficial muscular aponeurotic system) which is fibro fatty and lymphatic fascial tissue that contains the muscles for facial expressions.

Underneath the SMAS layer is a layer that has traditionally been a loose areola tissue layer. We now understand that this deeper layer comprises of multiple discrete fat compartments and can be sometimes referred to as the deep fat layer. Beneath this is the periosteum of the facial skeleton.

 Ligaments

There are several ligaments that run through these tissue plane, from deep to superficial. The true retaining ligament run from the periosteum through the SMAS layer to insert into the dermis. These include the orbital retaining ligament, the zygomatic cutaneous ligament and the mandibular ligament. Several smaller ligaments are also present which can be described as condensations of fascia which run from the SMAS layer superior to the skin. The role of these multiple myocutaneous ligaments is to allow the transmission of movements of the muscles of facial expressions to the skin.

Arterial Blood Supply

The face contains two main arterial blood supplies. One arising from the external carotid artery system and one arising from the internal carotid artery system.

The external carotid artery gives rise to the facial artery which crosses the mandible, entering the face at the junction between the posterior one third and the anterior two thirds of the body of the mandible. This also corresponds to the anterior border of the masseter muscle and this can be palpated at this point as well as being identified by a facial artery notch that runs inferiorly along the edge of the mandible. This artery runs underneath the SMAS layer and traverses superiorly and medially towards the corner of the lip before giving rise to an inferior labial and superior labial artery, and then continuing in the deep nasal labial fat as the nasolabial artery. This continues along the side of the nose, as the angular artery, and gives rise to an alar branch to supply the skin over the ala of the nose and a lateral nasal branch to supply the skin of the lateral nose.

A further branch of the carotid artery is its terminal branch, the superficial temporal artery which divides into two main branches and supplies the skin of the temporal and forehead area.

The second main supply to the face arises from the internal carotid artery which gives rise via it’s various branches to the supraorbital and supratrochlear artery. As the facial artery makes its way from the mandible notch to the oral commissure, it branches to the inferior labial artery and the superior labial artery and continues towards the nasal alar and meets the angular artery.

The inferior labial artery comes off the facial artery and penetrates the orbicularis oris and runs a tortuous course along the inferior “wet/dry” border. It supplies blood to the lower lip and mucous membrane. The artery anastomoses with the inferior labial artery on the opposite side.

The superior labial artery is larger than the inferior artery and runs along the inferior “wet” border. It has 2-3 branches towards the nose including the alar branch and nasal septal.

Avoid injecting

Avoid injecting the wet/dry border on the lower and upper lip.

Avoid injecting perpendicular to the vermillion border unless vessel mapped and or aspirate.

As a guide place your little finger, laterally from the oral commissure to avoid the facial artery.

Difference between Arteries, Veins and Capillaries 

Danger zones:

Glabella

Temple

Nose

Perioral Area (Lips)

Infraorbital area region

Nasolabial Folds

Veins of the face have no valves which means free retrograde flow and

Higher risk of infection

Embolisation leading to blindness

Orbital and central nerve infection (Orbital Cellulitis and Cavernous Sinus Thrombosis)

Position of the Facial Nerves  

The facial nerve is the seventh cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue.

Salivatory Glands

Five nerve branches divide within the parotid gland.  There is a structure of lymphatic drainage within the area.

Langer’s Lines 

Langer’s lines, Langer lines of skin tension, or sometimes called cleavage lines, are topological lines drawn on a map of the human body. They correspond to the natural orientation of collagen fibres in the dermis and are generally perpendicular to the orientation of the underlying muscle fibre.