The laughter muscle (lat. Musculus Risorius) is a paired facial muscle that is responsible for the expression of joy and pleasure on the face, and also participates in the formation of a smile. It is located in the cheek area, on the lateral surface of the lower jaw, and starts from the zygomatic bone and the lateral surfaces of the branches of the jaws.
The laughter muscle has several names in Latin and Russian. In English-language literature it is called “risorius” (from Latin risus, “smile”), and in Russian it is called “the laughter muscle” or “lower cheek muscle.” It may also be called the “smile muscle” or the “large buccal muscle,” especially when describing facial anatomy in Latin.
In anatomy, the laughter muscle is designated as M. Risorius (Musculus Risorius), where the word “musculus” means “muscle” and “risorius” means “laughing”. In other languages, such as French and German, this muscle may be called the “muscle de la grimace” (French for “grimace muscle”) or “muscles des lèvres” (French for “cheek muscles”).
The function of the laughter muscle is to form an expression of joy and pleasure, which appears on the face in the form of a smile. It works together with other facial muscles and is involved in the formation of various expressions of emotions, such as joy, surprise, anger, fear, etc.
In addition, the laughter muscle plays an important role in speech articulation. It helps open the mouth, which allows you to pronounce sounds and words, expressing various emotions. In addition, it is involved in the formation of sounds that accompany laughter and smiling, such as “ha-ha-ha” and “hee-hee-hee”.
The importance of the laughter muscle for the expression of emotions and articulation of speech makes it an important object of study in the fields of neurophysiology and psychophysiology.