Extended data:
The masseter muscle is one of the masticatory muscles. It begins at the lower edge and inner surface of zygomatic arch and ends at the lateral side of masseter tubercle and mandibular branch. The contraction of masseter muscle, temporal muscle and medial pterygoid muscle can hold up the mandible (closed mouth). Dominated by the mandibular nerve masseter nerve. It is of great significance in chewing function.
The masseter muscle is influenced by many factors, such as race, sex, age and face shape. Generally speaking, men are more developed than women, and the elderly are more developed than young people, but the decisive factor is chewing. Because of its contraction, people who often love hard food will develop masseter muscles accordingly. For example, people who often eat beef jerky and chew gum have more developed masseter muscles than ordinary people.
Reference source: Baidu Encyclopedia-Masseter Muscle