Anatomy

 

Transcript

We will now examine the cheek, which forms a substantial area of the midface. Within the cheek, there are several distinct regions. The first is the lateral upper cheek which is formed by the zygomatic arch and overlying fat. We then have the anterior cheek and the sub-malar region, which is also known as the buccal region. Finally, we have the sub-zygomatic region, which is sometimes called the pre-auricular area. Each of these regions has different treatment indications, and is associated with different techniques. Looking at the key layers within the cheek, we can see that these include the skin, beneath which are the 3 subcutaneous fat pads. Next, we have the muscles of the cheek and underlying these we find the deep fat. This includes the suborbicularis oculi fat, also known as the SOOF, and also the deep medial cheek fat. Finally, we have the periosteum.

 

As we begin to examine the numerous key muscles in this region, it is important to understand their origins, insertions, and actions. The orbicularis oculi originates from the frontal bone, the medial palpebral ligament, and the lacrimal bone. It then inserts into the lateral palpebral raphe. This muscle contains different sections, which include the orbital section, pre-tarsal, and pre-septal muscles. The zygomaticus major arises from the anterior aspect of the zygomatic arch then inserts into the modiolus of the mouth. Its action is to draw the angle of the mouth both upward and lateral. The zygomaticus minor arises from the zygomatic bone and then inserts into the skin and muscle of the upper lip. When it contracts, it elevates and everts the upper lip. The levator labii superioris arises from the medial infraorbital margin and then inserts into the skin and muscle of the upper lip. Its action is to elevate the upper lip. The levator labii superioris alaeque nasi is a small but long muscle that originates in the medial maxilla. It then bifurcates to insert into the medial orbicularis oris and the nasal alar. Its insertion into the medial part of the nasolabial fold contributes to the fold arising. It also flares the alar base superolaterally, leading to a drooping nasal tip that occurs upon smile and is also implicated in bunny line formation. The risorius arises from the parotid fascia and inserts into the modiolus of the mouth. When it contracts, it draws back the angle of the mouth. Finally, the buccinator arises from the alveolar processes of both the mandible and the maxilla, and from the temporomandibular joint. It then inserts into the orbicularis oris fibres. Its action is to compress the cheek against the teeth.

 

When we treat this region, we need to be aware of a number of areas where there is a potential for damage of anatomical structures. The blood vessels at risk include the transverse facial artery, which has a variable course and is at risk in all areas of the cheek. The zygomaticofacial artery is at risk during cheekbone augmentation. Finally, the facial artery can be compromised if it is more lateral than anticipated and affected within the submalar hollowing. In addition, we have the structures that pass through the infraorbital foramen, an opening in the maxillary bone just below the infraorbital margin. The structures passing through the infraorbital foramen include the infraorbital artery, vein, and nerve. Other structures at risk in the subzygomatic area include the parotid gland, parotid duct, and buccal branch of the facial nerve.

 

Within the cheek area, patients can experience the development of a nasolabial fold. These develop due to excessive accumulation of fat, reabsorption of the bone, skin laxity, or because there is a slight depression within the skin, which is the most amenable to treatment. On the screen, you can see the changes that take place during the development of the nasolabial fold. We have a number of goals to achieve when we treat this area. We want to define and beautify the cheekbone region, restore youthful volume to the anterior cheek, provide lift within the subzygomatic area, and cause a decrease to the nasolabial fold. Where we have injections that overly the bone, the injection should be deep. Elsewhere in the cheek, where there is no bony support, the injections must be superficial.