To correct an asymmetric smile, which is caused by abnormal motion of the zygomaticus major muscle
, the toxin is injected in the lateral margin of the muscle to a depth of -4.6 mm (Fig.
However, the activities of the zygomaticus major muscle
did not show any sign of premier expression, which indicated that the premier expression was sensitive to unpleasant stimuli and might only exist as a negative signal.
These researchers instructed their test subjects to view cartoons while holding a pen in their mouth in such a way that either the zygomaticus major muscle
(which is used when laughing and smiling) or its antagonist, the orbicularis oris muscle, was contracted.
Some authors consider that the SMAS encloses the mimetic muscles , while others affirm that the SMAS finalizes in the zygomaticus major muscle
Although puffing the cheeks caused some flattening of the buccal fat pad, the anatomic structures related to the buccal space--such as the zygomaticus major muscle
, the parotid duct, and the facial vein--were all equally visible on both series of scans.
* The anterior lobe is located below the zygoma, extending to the front of the buccinator, maxilla and the deep space of the quadrate muscle of the upper lip and zygomaticus major muscle
. The canine muscle originates from the infraorbital foramen and passes through the medial part of the anterior lobe.
The researchers observed that the patients twitched their smiling-specific zygomaticus major muscle
when presented with happy pictures, and the frowning-specific corrugator supercilii muscle when presented with fearful pictures.
Following Zhu and Suzuki (2016), we measured reactions of the corrugator supercilii muscle and zygomaticus major muscle
. Facial reactions located in the corrugator supercilii muscle have proven sensitive to negative emotions (e.g.
Zygomatic ligament was located lateral to the origin of the zygomaticus major muscle
, at the junction of the zygomatic arch and the body of the zygomatic bone (Fig.
The results for the zygomaticus major muscle
are presented in Figure 3.
For example, when observing a happy face, one tends to activate the zygomaticus major muscles
, which turn the corners of the mouth upwards into a smile, as well as the orbicularis oculi muscles, which are responsible for squinting the eyes.
In addition, to ascertain whether or not smile types would have differential effects on ERN amplitudes, we distinguished between a genuine Duchenne smile and a standard smile: A standard smile engages only the zygomaticus major muscles
around the mouth, whereas a Duchenne smile engages both the zygomaticus major muscles
and the orbicularis oculi muscles surrounding the eyes (Duchenne de Boulogne, 1862/1990; Ekman & Davidson, 1993).