The zygomaticus major muscle is a muscle of facial expression that is located in the face. It is one of the muscles that is responsible for controlling the movement and expression of the face. The zygomaticus major muscle is located in the skin of the face and is attached to the zygomatic bone, also known as the cheekbone.
Location
The zygomaticus major muscle is located in the skin of the face and is attached to the zygomatic bone, also known as the cheekbone. It is located in the middle third of the face, between the risorius and the levator labii superioris muscles.
Structure (Anatomy)
The zygomaticus major muscle is a thin, elongated muscle that is located in the skin of the face. It is composed of long, slender fibers that are oriented horizontally and run parallel to the skin surface. The muscle is attached to the skin at one end, and to the zygomatic bone at the other end.
The zygomaticus major muscle is innervated by the facial nerve, which supplies it with the necessary nerve impulses to contract and relax. The muscle receives its blood supply from the facial artery, which is a branch of the external carotid artery.
Function
The main function of the zygomaticus major muscle is to assist in the movement and expression of the face. It is responsible for pulling the corners of the mouth laterally and upwards, creating a smile or a smirk.
The zygomaticus major muscle works in conjunction with other facial muscles to produce a range of facial expressions. For example, when the zygomaticus major muscle contracts, it can be combined with the contraction of the risorius muscle to produce a full smile. Alternatively, it can be combined with the contraction of the levator labii superioris muscle to produce a sneer or a scowl.
In addition to its role in facial expression, the zygomaticus major muscle may also play a role in speech and vocalization. It is thought that the zygomaticus major muscle may help to shape the oral cavity and alter the position of the lips and tongue, which can affect the way that words are pronounced.
Clinical significance
Dysfunction of the zygomaticus major muscle can lead to problems with facial expression and communication. In some cases, an injury or damage to the facial nerve may cause the zygomaticus major muscle to become paralyzed, leading to a flat or expressionless appearance.
In rare cases, the zygomaticus major muscle may be affected by a condition called facial spasm, which is characterized by involuntary contractions of the facial muscles. Facial spasm can cause the zygomaticus major muscle to contract repeatedly, leading to an abnormal facial expression.
In addition to its role in facial expression, the zygomaticus major muscle may also be used as a diagnostic tool in some medical conditions. For example, some studies have suggested that a lack of zygomaticus major muscle activity may be a sign of depression or other mental health disorders.
