The fatty tissue of the face is divided into a superficial and a deep layer by the SMAS, with the superficial fat accounting for about 56% and the deep fat for about 44% [2]. The superficial fat consists of small fat lobules that are separated from each other by many connective tissue septa that run from the SMAS to the dermis. In contrast, the deep fat is composed of larger fat lobules and accordingly contains only a few connective tissue septa that run from the periosteum to the SMAS.

The fat in the superficial layer (Fig. 1) forms a cohesive cushion and is very well developed in the area of the glabella, in the cheek area, in the nasolabial fold, on the jowls and on the chin. In contrast, little superficial fat is found in the forehead, around the eyes, around the mouth and in the temple area. The superficial fat can be divided into different compartments, which are largely separated from each other by connective tissue, but partly also by muscles [3, 4, 5]. These compartments include the 3 cheek fat compartments (lateral-temporal, middle and medial cheek fat compartments), the nasolabial compartment, the chin compartment, the labiomandibular and the jowl compartment.

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The lateral temporal and medial compartments have common upper and lower limits. The upper limit of these two compartments is formed by the zygomatic retaining ligaments (Fig. 2), while both are limited downwards by the platysma-mandibular ligaments. The posterior border of the lateral temporal compartment is formed by the platysma-auricular ligaments, while the anterior border of the middle cheek compartment is only partially formed by ligaments: in the upper area, the zygomaticus major muscle forms the anterior border, while in the lower area, the masseter-cutaneous ligaments form the anterior border. The two compartments are separated from each other by the parotid-masseteric subcutaneous septum. Since the septum runs in an antero-lateral direction, the medial cheek fat compartment is partially overlaid by the lateral-temporal compartment. Neither compartment usually contains a particularly thick layer of fat.

The medial cheek compartment, also known as the superficial malar fat pad, usually has the shape of a standing triangle. The orbital septum forms the upper boundary towards the eye region. The lateral demarcation to the middle cheek compartment is formed by the zygomaticus major muscle, from the epimysium of which connective tissue strands run into the dermis. The medial boundary of the medial cheek compartment is formed by the maxillary part of the bucco-maxillary ligaments.

The nasolabial compartment (= nasolabial fold) is located lateral to the nasolabial furrow. The nasolabial fold thus forms the medial boundary of the compartment and is caused by the mimic muscles that radiate into the upper lip, but also by the m. depressor anguli oris. The lateral boundary of the nasolabial compartment is formed by two bands: in the upper area by the maxillary part of the bucco-maxillary bands, in the lower area by the buccal part of these bands.

The chin compartment is bounded at the bottom by the submental ligaments, which in many cases are very pronounced and form a clearly visible boundary with the submental region. However, in some cases these ligaments may be absent, resulting in a smooth transition from the chin to the submental region. The lateral boundary of the chin compartment is formed by the labiomandibular groove. It begins at the corner of the mouth and follows the medial edge of the depressor anguli oris muscle down to the origin of the mandibular holding bands. The furrow is thus formed by the skin insertion of the medial edge of the depressor anguli oris muscle. The upper boundary of this compartment is formed by the mentolabial furrow, which is caused by the insertion of the mentalis muscle.

The labio-mandibular compartment (= labio-mandibular fold, marionette line) is located laterally to the above-mentioned labio-mandibular groove, which thus forms the medial boundary of this compartment. The lateral border is formed by the masseter-cutaneous retaining bands, which radiate into the skin of the labiomandibular fold, and the lower border by the mandibular and platysma-mandibular bands.

The jowl compartment is located under the middle jowl fat compartment in a completely enclosed space. Its upper boundary is formed by the platysma-mandibular suspension ligaments, and it is demarcated towards the front and up against the labiomandibular compartment by the mandibular suspension ligaments. The paramedian platysma retaining bands form the anterior border towards the submental region, while the submandibular platysma retaining bands form the posterior border. The latter two bands are localised at the neck, originate from the neck fascia and fix the platysma. The platysma itself forms the floor of this compartment.

The deep fat of the face (Fig. 3) does not form such a uniform layer, but consists of discontinuous fat pads. These are mainly found in the temple area, around the orbit and in the cheek area. In the temporal region there is a fat body in a completely enclosed space between the two leaves of the fascia temporalis (not to be confused with the superficial fascia temporalis!) and the zygomatic arch (temporal fat body). One layer deeper, under the deep leaf of the fascia temporalis, lies the temporal extension of the corpus adiposum buccae (Bichat) (see also Fig. 4).

In the area around the orbit, deep fat is found on the one hand in the upper area behind the orbicularis oculi muscle and is referred to here as ‘retroorbicularis oculi fat’ (ROOF). But a deep fat pad can also be found in the area of the lower lids under the orbicularis oculi muscle, the ‘suborbicularis oculi fat’ (SOOF). This fat can pass through the muscle and thus lead to a pseudo herniation. The SOOF extends far down under the lower edge of the orbicularis oculi muscle into the cheek region, so that four layers of fatty tissue can be found here (Fig. 5) [6].

The SOOF is located under the medial cheek fat compartment (= superficial malar fat pad). This lies in the cheek area on the zygomaticus major muscle and the levator labii superioris muscle. Underneath the SOOF is another fat body, which lies in the layer between the levator labii superioris muscle and the levator anguli oris muscle, the malar fat body (= deep malar fat body). Deep in this in the 4th layer and under the levator anguli oris muscle, in the canine fossa, is the small premaxillary fat body. This lies directly above the fornix superior of the oral cavity at the level of the dens caninus. It is connected to the deep malar fat pad at the side of the levator anguli oris muscle. Another deep fat pad in the cheek region is the corpus adiposum buccae (Bichat), which is enclosed in its own capsule. Its main part is located in the depth of the lateral facial region. Its temporal extension runs medially from the zygomatic arch to the temple area, where it lies under the deep leaf of the fascia temporalis. Its masseter extension lies on the buccinator muscle and is covered by the masseter muscle.