These muscles are also called mimetic muscles. When they contract, the skin moves. These muscles also cause wrinkles at right muscles of facial expression pdf to the muscles’ action line. Use of these muscles is noted during an extraoral examination, assuring function of the nerve to these muscles.
The platysma is innervated by the facial nerve. Although it is mostly in the neck and can be grouped with the neck muscles by location, it can be considered a muscle of facial expression due to its common innervation. The stylohyoid muscle, stapedius and posterior belly of the digastric muscle are also innervated by the facial nerve, but are not considered muscles of facial expression. An inability to form facial expressions on one side of the face may be the first sign of damage to the nerve of these muscles.
Damage to the facial nerve results in facial paralysis of the muscles of facial expression on the involved side. The parotid gland can also be damaged permanently by surgery or temporarily by trauma.
Through electric stimulation, he determined which muscles were responsible for different facial expressions. Charles Darwin would later republish some of these photographs in his own work on the subject, which compared facial expressions in humans to those in animals. A facial expression is one or more motions or positions of the muscles beneath the skin of the face. Facial expressions are a form of nonverbal communication.
They are a primary means of conveying social information between humans, but they also occur in most other mammals and some other animal species. The pioneer F-M Facial Action Coding System 2.
Freitas-Magalhães, and presents about 2,000 segments in 4K, using 3D technology and automatic and real-time recognition. Humans can adopt a facial expression voluntarily or involuntarily, and the neural mechanisms responsible for controlling the expression differ in each case.