M. Buccinator Anatomy and Inflammatory Pathways PDF

# M. Buccinator - M. buccinator originates from the **processus alveolaris** just outside the middle of the upper molar roots. - M. buccinator does not originate from the rest of the teeth in the upper jaw, and therefore cannot close the mouth. - The lower fold is deeper at the front (1) next to th...

# M. Buccinator - M. buccinator originates from the **processus alveolaris** just outside the middle of the upper molar roots. - M. buccinator does not originate from the rest of the teeth in the upper jaw, and therefore cannot close the mouth. - The lower fold is deeper at the front (1) next to the labial frenulum than at the back (2) next to the molars. - At the back, depth is unusual because m. buccinator (1) originates from **crista buccinatoria**, which runs next to the necks of the lower molars. ## Gingiva - The mucous membrane on the **processus** and **pars alveolaris** includes **free marginal gingiva (1)**, which forms **interdental papillae (4)** between teeth, **attached/fast gingiva (2)** and **alveolar mucosa (3)**. - The alveolar mucosa has a weak binding while the attached gingiva is tightly bound. - The border between the loosely bound, bright red alveolar mucosa (3) and the attached gingiva (2) is the **mucogingival junction** or line. ## Mucogingival junction - The mucous membrane's attachment differs depending on its location in the vestibule. - Tightest binding is on gingiva, followed by lips and cheeks. - The mucous membrane of the folds is extremely loosely bound. - Loose binding in the folds is necessary for closing the mouth. - Patients with extensive scars in the folds, for example after burns, have difficulty opening their mouths. This is due to the scar tissue being tight, and the mucous membran losing its loose attachment. - Tight attachment on the inside of cheeks and lips makes it easier to avoid biting your cheeks. A loose mucous membrane would be more likely to get pinched when chewing. - Gingiva is particularly tightly attached because it must withstand strong mechanical stress during chewing. - A mucous membrane with pronounced mechanical function should not be able to 'slip' on its base. ## Betændelsesveje (Inflammatory pathways) - Besides determining the depth of the folds at the back, **m. buccinator** is important for the spread of inflammatory processes from molars to the soft tissues of the cheek. - If an infection from a molar in the upper jaw breaks through the bone (fig. 64) (3) below the origin of m. buccinator (1), the infection will spread (2) under the mucous membrane (4) into the **tela submucosa (5)**, in other words 'inside' m. buccinator. - The same applies to the lower jaw, if the infection breaks through the bone (6) above the origin of m. buccinator (1). - However, if the infection breaks through the bone 'outside' the origin of m. buccinator (4), it will spread into the **subcutis (3)**. ## Analgesi (Anaesthesia) - When performing **foramen mandibulare anaesthesia**, the tip of the needle is advanced through the mucous membrane lateral to the **plica** and **raphe pterygomandibularis (1)**. - The needle then passes through **tunica mucosa (2)**, **tela submucosa (3)**, **m. buccinator (4)** and continues into the connective tissue (6) in the **fossa infratemporalis**, towards the inside of **ramus mandibulae (7)**, behind **crista temporalis (5)** with the medial part of the temporalis tendon. - If the needle is mistakenly advanced through the mucous membrane medial to the **raphe pterygomandibularis (1)**, it will pass through the **pars buccopharyngea (19)** and will therefore be too far medial, ending in **m. pterygoideus medialis** (shaded area (18) to the right of the needle). - If the tip of the needle is in the muscle it is difficult to change the direction of the needle and make contact with the bone. - In the best case, the anaesthesia will be insufficient, and if you try to 'turn' the needle there is a risk of it breaking. - The needle should be inserted through the mucous membrane at the deepest point of the concave 'arch', which the front edge of **ramus mandibulae** forms (fig. 69 a). - Shortly after insertion, a depot of **n. lingualis** is placed. - Then the needle is advanced backwards along the medial surface of **ramus mandibulae** to make contact with the bone behind the foramen. - The depot is placed at **n. alveolaris inferior**. ## Innervation of the mucous membrane - Nerves supplying the **vestibulum oris**, including the **facial gingiva**, in the upper jaw come from **n. maxillaris and n. infraorbitalis (1)**, and in the lower jaw from **n. mandibularis and n. alveolaris inferior (2)**. - The **facial gingiva** next to the molars in the upper jaw and the adjacent part of **vestibulum oris** are innervated by **rami gingivales** from **rami alveolares superiores posteriores (2)**, branches of **n. maxillaris**. - The **facial gingiva** next to premolars, canine and incisors in the upper jaw and the adjacent part of **vestibulum oris** are innervated by **rami labiales superiores** from **n. infraorbitalis (1)**. - In the lower jaw the **facial gingiva** next to the molars and the adjacent part of **vestibulum oris** are innervated by **n. buccalis (3)** from **n. mandibularis**, while