PRIME Journal Vol. 12 Issue 1

A BEAUTIFUL FACE, IN GENERAL, requires harmonious proportions of the facial horizontal thirds and vertical fifths. The chin is of great importance for a beautiful face in both male and female patients. Abnormal proportions between the chin, nose, and the rest of the face are features for the diagnosis of short or long face patterns and micrognathia. To achieve balance in a short face the chin should be elongated, for example, and in a recessed chin, it should be projected. In mild and moderate cases of a recessed chin, injectable fillers can be used, such as hyaluronic acid, calcium hydroxyapatite, and a new option with both substances in the same syringe is also available on the market. Chin deformities are the most common bony abnormality in the face 1 and the majority can be treated with fillers. Fillers to the chin can be used for beautification and/or rejuvenation. In the face, the ageing process leads to skin atrophy, the redistribution of subcutaneous fat, and bone remodelling and resorption. In the lower face, themandibleundergoes anterior and inferior resorption, which the loss of teeth can worsen. The chin becomes more anterior and shorter with ageing 2 , resulting in loss of jawline definition and facial contour, and modifies the facial proportions. The ageing process modifies all layers of the facial soft tissue as well as the skeleton 3 . KEYWORDS Chin, dermal filler, face, male patient, female patient GRASIELA CÁSSIA MONTEIRO, MD, MSC, Professor of Cosmetic Dermatology at Ambulatory of Sanitary Dermatology–Porto Alegre (RS), Brazil email: gcmonteiro@hotmail. com Anatomy of the chin Bone The main structural component is the mandible in the sagittal midline and the mandibular symphysis. Other points include: ■ Menton (Me): lowest point on the contour of the mandibular symphysis ■ Gnathion (Gn): most anteroinferior point along the contour of the mandibular symphysis ■ Pogonion (Pg): most anterior point along the contour of the mandibular symphysis. Soft tissues Anterior to the labiomandibular sulcus, from superficial to deep, there is skin, subcutaneous fat, muscles of facial expression (depressor anguli oris, platysma, depressor labia inferioris, and mentalis), deep labiomandibular fat, and deep mental fat in the chin, and periosteum. The inferior margin of the labiomandibular sulcus is formed by the mandibular ligament, anterior to the jowls 4 . Inferior to the chin, there are insertions of the muscles platysma, genioglossus, and geniohyoid 1 . Vasculature The primary blood supply to the chin are the mental arteries, which exit the mental foramen on the lateral chin, in line with the vertical axis of the second inferior premolar teeth 5 . The mental veins also exit from the mental foramen. The mental arteries are terminal branches of the inferior alveolar arteries, which are branches of themaxillary artery. The inferior labial artery and labiomental artery provide further blood supply to the region. The submental artery is a cervical branch of the facial artery. It runs fromtheexit of the submandibular gland over themylohyoid and crosses themandible near the mandibular symphysis 2 . Nerves The mental nerve, a branch of the trigeminal nerve, exits the mental foramen and provides sensory innervation. In the lower face, the motor innervation is given by the branches of the facial nerve, the buccal and marginal mandibular nerves. Chin assessment The chin is of great importance for facial attractiveness in men and also in women. The injector should identify chin projection, length and width, dental occlusion, and nasal relationship. It is essential to analyze the labiomental sulcus, mandible angle, pre-jowl sulcus, and cervicomental angle. The chin should be assessed via horizontal, vertical, and oblique measurements. It is important to identify facial patterns and ascertain whether facial width and length are balanced or whether the patient can be classed as either dolichofacial (long face) or brachyfacial (short face). The subjective facial analysis includes the relationship between maxillae and mandible and the dental occlusion. It is also important to diagnose if the patient is orthognathic, prognathic, or retrognathic. On | INJECTABLES | AESTHETIC FEATURE | January/February 2022 17