The buccinator is a broad, thin, quadrilateral muscle that forms the deep structure and lateral wall of the oral cavity. It is a primary component of the facial musculature and plays a significant role in various daily activities, coordinating with other muscles of the mouth and jaw for complex movements.
Anatomy and Exact Placement
The buccinator muscle occupies the space between the upper jawbone (maxilla) and the lower jawbone (mandible) on the side of the face. It is positioned deep to the more superficial layers of skin, fat, and other facial muscles.
The muscle originates from three areas. Its fibers arise from the outer surfaces of the alveolar processes of both the maxilla and the mandible, particularly near the molar teeth. A third point of origin is the pterygomandibular raphe, a fibrous seam that connects the buccinator to the superior pharyngeal constrictor muscle at the back of the mouth.
From these origins, the buccinator fibers travel forward to converge at the corner of the mouth. They insert into the dense, muscular knot known as the modiolus, where they blend with the fibers of the orbicularis oris muscle, which encircles the mouth. This blending allows for coordinated movement of the lips and cheeks.
The buccinator relates specifically to surrounding structures. On its lateral side, the muscle is covered by the buccal fat pad and the buccopharyngeal fascia. Conversely, the medial surface is lined by the submucosa and mucosa of the oral cavity, forming the inner lining of the cheek.
The parotid duct (Stensen’s duct) carries saliva from the parotid gland. This duct must pierce through the buccinator muscle to open into the oral cavity, typically near the second maxillary molar tooth. Motor control is supplied by the buccal branch of the facial nerve (Cranial Nerve VII), making it one of the muscles of facial expression.
Essential Functions in Oral Movement
The primary mechanical action of the buccinator is to press the cheeks inward against the teeth. This constant pressure is crucial during mastication, or chewing, as it keeps the food bolus positioned centrally on the occlusal surfaces of the molar teeth. Without this action, food would easily slip into the space between the teeth and the cheek, known as the oral vestibule.
The muscle’s contraction also prevents the inner lining of the cheek from being accidentally caught and bitten between the teeth while chewing. The buccinator assists in deglutition, or swallowing, by helping to move the food bolus from the oral cavity toward the pharynx.
The buccinator is adapted for movements involving air pressure within the mouth, earning it the historical name “trumpeter’s muscle.” Its contraction flattens the cheek, enabling actions such as blowing a wind instrument, whistling, or forcefully expelling air. In newborns, the buccinator is activated early, as its sucking function is necessary for suckling during infancy.
Relevance in Health and Dentistry
The integrity and function of the buccinator muscle are connected to oral health and medical conditions. When the facial nerve is damaged, such as in cases of facial nerve paralysis or Bell’s Palsy, the buccinator muscle can become weakened or paralyzed. This loss of function leads to difficulties in manipulating food during chewing, resulting in the collection of food particles in the cheek pouch.
Buccinator weakness also increases the risk of accidental cheek biting and can impair speech articulation due to the loss of cheek tension. Excessive tension in the buccinator, known as hyperactivity, can exert pressure on the underlying jaw structures. This sustained force may contribute to conditions like narrow dental arches and certain types of dental malocclusion.
In prosthodontic dentistry, the buccinator’s action is important for the stability of removable dental appliances, like full dentures. The muscle grips the polished surface of the denture, helping to hold it securely in place during speaking and eating. Surgeons also utilize the muscle, as the ease of lifting it makes it a valuable source for a muscle flap in reconstructive surgery to repair defects within the oral cavity.