Anatomy of the Buccinator Muscle
The buccinator muscle is a quadrilateral muscle occupying the deepest layer of the cheek, with origins from three distinct sites: the maxillary tuberosity superiorly, the pterygoid hamulus centrally, and the internal oblique line of the mandible (retromolar area) inferiorly, where it shares a common tendon with the deep temporalis muscle 1.
Origins and Attachments
The buccinator demonstrates a three-part structural organization 1, 2:
- Superior fibers: Originate from the maxillary tuberosity
- Middle fibers: Originate from the pterygoid hamulus with a dual attachment mode - tendinous at the root (approximately 0.61 mm from the maxillary tuberosity) and periosteal at the tip (approximately 2.37 mm away) 3
- Inferior fibers: Originate from a small retromolar area on the internal oblique line of the mandible, sharing a common tendon with the deep temporalis muscle 1
Critical Anatomical Revision
Traditional descriptions of a pterygomandibular raphe connecting the buccinator to the superior pharyngeal constrictor are anatomically incorrect 1. Instead, the border between these muscles is clear, with muscle fibers following different directions. Some horizontal fibers are continuous between the buccinator and superior constrictor, but no distinct raphe structure exists 1.
Layered Architecture
The buccinator is organized into three distinct layers 2:
- Superficial layer: Contains upper and lower oblique parts
- Deep layer: Contains the middle transverse part
- Integration with orbicularis oris: The middle transverse part continues directly with the inner marginal parts of both superior and inferior orbicularis oris without connecting to the modiolus 2
Insertion and Modiolus Connection
The muscle fibers demonstrate partial connection at the modiolus and partial direct continuation 2:
- Upper and inner oblique parts connect at the modiolus in a horizontal direction (second layer)
- Middle transverse fibers bypass the modiolus entirely, continuing directly with the orbicularis oris (third layer)
Connective Tissue Relationships
The buccinator maintains intimate relationships with surrounding connective tissue through fibrous septa 4:
- Type I collagen septa extend from submucosa through the muscle to the skin, containing elastic fibers
- Type III collagen septa run from the lateral muscle surface to the skin
- These connections develop early (8-17 weeks) and persist throughout life 4
Functional Anatomy
Parotid Duct Relationship
Distinct muscle fibers from the buccinator extend to and insert into the terminal portion of the parotid duct 5. These fibers demonstrate three anatomical patterns:
- Type I (45.5%): Fibers originate from both anterior and posterior aspects of the duct
- Type II (31.8%): Fibers originate from and insert into the anterior aspect
- Type III (22.7%): Fibers originate posteriorly and run anteriorly toward the duct 5
These specialized fibers play a role in salivary secretion by mechanically assisting duct function during muscle contraction 5.
Clinical Implications
Surgical Considerations
The close proximity of the buccinator to the maxillary tuberosity (mean 0.61 mm at the pterygoid hamulus root) creates significant risk during pterygoid implant placement 3. The dual attachment mode means:
- Implant perforation near the hamulus root poses higher risk of muscle injury due to tendinous attachment
- The tip region (2.37 mm distance) provides slightly more safety margin with periosteal attachment 3
Anatomical Variability
Substantial individual variation exists in maxillary tuberosity morphology, with some specimens showing low bone volume fraction (BV/TV), which increases surgical unpredictability 3. Understanding these variations is essential for safe implant placement.
Innervation Context
While the buccinator's detailed innervation is not the focus here, it receives motor innervation from the facial nerve (CN VII), which courses through the parotid gland region 6. The facial nerve's buccal branches specifically innervate this muscle of facial expression.