Buccinator is a thin quadrilateral facial muscle that is the main component of the cheek. It belongs to the buccolabial group of facial muscles along with levator labii superioris alaeque nasi, levator labii superioris, zygomaticus major, zygomaticus minor, levator anguli oris, risorius, depressor labii inferioris, mentalis, orbicularis oris, incisivus superior and inferior muscles.
Buccinator has a number of origin points which is the basis for subdividing the muscle fibers into superior, inferior and posterior parts.
This muscle is the main muscle of the cheek, that provides it with structure and tightness. It compresses the cheek against the molar teeth, which is important to keep the food bolus central in the oral cavity, and to prevent the cheeks from being bitten during mastication. In addition, the buccinator is the main muscle involved in playing wind instruments, as it expels air from the distended cheeks.
|Origin||(External lateral surface of) Alveolar process of maxilla, buccinator ridge of mandible, pterygomandibular raphe|
|Insertion||Modiolus, blends with muscles of upper lip|
|Function||Compresses cheek against molar teeth|
|Innervation||Buccal branch of facial nerve (CN VII)|
|Blood supply||Buccal artery (maxillary artery), facial artery|
This article will teach you all you need to know about the anatomy and functions of the buccinator muscle.
Origin and insertion
Buccinator muscle can be divided into three parts based on its origin points; superior and inferior parts that oppose each other, and the deeply located posterior part. Its superior part arises from the outer surface of the alveolar process of maxilla opposite to the three maxillary molar teeth. The inferior part arises from the buccinator ridge of mandible, opposite to the three mandibular molar teeth. The posterior part of the buccinator originates from the anterior margin of pterygomandibular raphe, a tendinous band behind the third molar spanning from the pterygoid hamulus to the posterior end of the mylohyoid line. Additionally, some fibers of the buccinator arise from the pterygomaxillary raphe, a fibrous band that extends from the pterygoid hamulus to maxillary tuberosity.
Converging towards the angle of the mouth, the three parts of buccinator fill the space between the upper and lower jaws. At the angle of the mouth, the buccinator fibers interlace with other muscles that attach at the same site, including orbicularis oris, risorius, depressor anguli oris and zygomaticus major. These muscles blend and form a dense fibromuscular mass called the modiolus.
After forming the modiolus, the fibers of the buccinator continue towards the upper and lower lips to comprise the peripheral part of orbicularis oris muscle.
- The uppermost and lowermost fibers of the buccinator diverge and enter the superior and inferior lips, respectively.
- The central fibers of the buccinator split into two and decussate so that the inferior half enters the superior lip, and the superior half enters the inferior lip.
The buccinator is the main component of the cheeks along with a considerable amount of subcutaneous fat. The buccal fat pad (of Bichat) covers the outer surface of the deep part of buccinator, separating it from the ramus of mandible, masseter and temporalis muscles.
Buccinator lies in the same plane and anteriorly to the superior pharyngeal constrictor, being separated from it by the pterygomandibular raphe. Both muscles are covered by the buccopharyngeal fascia. The posterior border of the buccinator is pierced by the tensor veli palatini near its attachment point to the pterygomandibular raphe.
Superior and inferior parts of the muscle lie deep to the zygomaticus major, risorius, levator and depressor anguli oris muscles. This surface is also crossed by the facial artery and vein and the branches of facial (CN VII) and buccal nerves. The duct of the parotid gland courses over this surface as well, and pierces the buccinator at the level of the third upper molar tooth. It then courses shortly over its deep surface and opens into the oral cavity second upper molar tooth. The deep surface of the muscle is related to the structures of the oral cavity; buccal glands and mucous membrane of the mouth.
Buccinator is innervated by the buccal branches of facial nerve (CN VII).
Buccinator receives arterial blood supply mainly from the buccal artery, a branch of the maxillary artery; and some branches of the facial artery.
Buccinator maintains the tightness of the cheeks and presses them against the teeth during chewing. It also assists the tongue to keep the bolus of food central in the oral cavity. This function is important to prevent it from escaping into the oral vestibule, as well as pushing any food that entered the vestibule back into the oral cavity. Buccinator also prevents cheeks from inverting in between the occlusal surfaces of the teeth and being bitten.
The buccinator muscle has another interesting function, and that is expelling the air from the inflated vestibule while playing a wind instrument such as the trumpet. This is why the buccinator muscle is also called the "trumpet muscle".