The upper face, including the frown, crows feet, and forehead, has historically been the most common and well-known area to use anti-wrinkle injections. The action of anti-wrinkle injections in these areas help to reduce excessive amounts of muscle activity to help reduce lines or wrinkles in these areas.
In the neck and lower face, anti-wrinkle injections can also be used to modulate the action of the muscles in this area. By targeting certain muscles in the lower face, it is possible to change their effect on the mouth, jawline, and neck. For example, it is possible to help to lift the mouth corners by the placement of anti-wrinkle injections in the muscle that pulls the mouth corners down. Unlike upper face anti-wrinkle injections, lower face anti-wrinkle injections are generally used to lift the lower face, mouth and neck, rather than to prevent the formation of wrinkles. Generally, the muscles of the lower face and neck that are targeted are those that pull the face down. Relaxation of these muscles with anti-wrinkle injections therefore, leads to an overall increase in the relative strength of the upward pulling muscles.
Depressor anguli oris (DAO) - mouth corner depressors
One of the important muscles that is treated with lower face anti-wrinkle injections is the depressor anguli oris. It attaches to the mouth corner and fans out from there to attach to the mandible (jawline). Its action is to therefore pull down the corners of the mouth. It is responsible for the ‘mouth frown’ when contracted. Relaxation of this muscle with anti-wrinkle injections leads to a relative increase in the strength of the muscles such as zygomaticus major which pull the mouth corners up. The final result is an improvement in the upturn of the mouth corners, and a reduction in the strength of the ‘mouth frown’ expression.
Mentalis - chin muscle
The mentalis muscle is attached to the bone on the tip of the chin and inserts into the skin of the chin. It is responsible for the upwards and inwards movement of the chin on contraction. On contraction, the mentalis muscle also causes the skin to have a ‘cobblestone’ appearance. Furthermore, it can help to close the mouth (lower lip), and is often constantly contracted in those who have some recession of the chin to keep the lips together.
Relaxation of this muscle can help to reduce the crease formed between the chin and the lower lip (known as the mental crease) and also reduce the cobblestone appearance when contracted.
Platysma - the neck muscle
The platysma is the large superficial sheet muscle that covers the neck and originates from the pectoralis muscle and inserts into the chin and jawline, the skin of the lower face and mouth corners. It pulls downwards on the neck, mouth corners, and the lower face, and often causes the skin of the neck to bunch up. On contraction, often platysmal bands are seen – these are strands of bunched up muscle that protrude from the neck.
Relaxation of this muscle can be performed just under the jawline. This technique is called the Nefertiti lift, as it helps to reduce the downwards drag of the muscle on the face and improve the jawline. This technique was created by Dr. Phillip Levy, and named after Queen Nefertiti who is portrayed in her bust as having a very sharp jawline.
Furthermore, when anti-wrinkle injections are injected into platysmal bands they can help to flatten them and make their appearance less obvious. Generally, injection of anti-wrinkle injections into the neck can help to stop the neck from bunching up and this may help reduce or prevent the appearance of horizontal neck bands.