Buccal Space Infection

Anatomy

Borders
•Medial

a. Buccinator muscle
b. Pterygomandibular raphe-a fibrous band separating the oral cavity and the oropharynx that lies between the tonsillar pillar and the retromolar trigone. It may serve as a bridge for pathology to extend from the retromolar trigone to the buccal space.

•Anterolateral

a. Orbicularis oris, risorius, zygomaticus major and minor muscles
b. Superficial layer of deep cervical fascia

•Posterior

a. Masticator space
b. Parotid gland
c. Posteromedially, at the level of the hard palate (the superior aspect of the buccal space), the superficial layer of the deep cervical fascia (SLDCF) extending between the masseter and the buccinator muscle is incomplete, allowing spread of pathology between the buccal space and the masticator space. More inferiorly, this fascia is complete.

•Inferior

a. Continuous with the submandibular space

•Superior

a. Continuous with the temporal fossa

Contents
•Buccal fat pad

a. Anterior compartment-superficial to the parotid duct
b. Posterior compartment-deep to the parotid duct, contains specialized syssarcosis adipose tissue, a remnant of the succatory fat pad that aids in muscle motion and is of lower CT attenuation and of higher fat signal on MRI than all surrounding fat, including the anterior compartment.
c. Four extensions

i. Lateral--follows the parotid duct to the parotid gland
ii. Medial--between the mandible and the maxillary sinus
iii. Superior--further divided into deep and superficial based on relation to the temporalis muscle. The deep portion is adjacent to the lateral orbital wall, anteromedial to the temporal tendon. ⁴ The superficial portion is between the temporalis muscle and the SLDCF.
iv. Anterior--superficial to the parotid duct

•Parotid duct

a. Separates the buccal space into anterior and posterior compartments
b. Passes through the buccinator muscle at a level opposite the second molar, causing slight retraction of the mucusa and the submucosal fat

•Facial artery

a. Supplies the nasolabial region; direct branch of the external carotid artery

•Buccal artery

a. Supplies the posterior buccal space; branch of the maxillary artery
b.Enters space through the incomplete SLDCF posteromedially; anastomoses with the facial artery

•Facial vein

a. Located just anterior to the parotid duct along the buccinator muscle
b.Drains the nasolabial region to the external jugular vein via the deep facial vein. Infection may spread from the deep facial vein to the pterygoid plexus, to the inferior orbital vein, to the cavernous sinus.

•Nerves

a. Buccal branch of the facial nerve CN V (sensory to skin and the mucosa of the buccal space; originates just below the foramen ovale and enters space through the incomplete SLDCF medially)
b.Buccal branch of CN VII (motor to muscles of facial expression, originates within the parotid gland and courses parallel to the parotid duct)

•Lymphatic drainage

a. Buccal nodes to the submandibular nodes to the jugular chain

•Accessory parotid tissue
•Minor salivary (buccal) glands

a. Mucosa covering the inner surface of the buccinator muscle

Pathology may arise de novo within the buccal space and spread to surrounding structures or may arise in surrounding structures and spread to the buccal space. As discussed above, the lack of fascial compartmentalization superiorly, inferiorly, and posteriorly permits the spread of pathology. Other routes of spread include: 1) the pterygomandibular raphe and retromolar trigone and 2) the deep facial vein.

Cellulitis/abscess of the buccal space
Infection is usually secondary to dental infections or manipulation of calculi within the salivary gland duct system, including the parotid and submandibular gland ducts. Infection can arise de novo in the buccal space or can secondarily involve the space from surrounding structures and compartments, especially the masticator space and submandibular space, both of which have areas of free communication with the buccal space. Cellulitis of the buccal space occurs more often in patients <3 years of age, with females and males affected equally. It commonly occurs in fall/winter and may be associated with ipsilateral otitis media. CT and MRI show edema and swelling of the subcutaneous fat . Abscess may be seen in all ages. Diabetes mellitus and Crohn's disease are risk factors. Crohn's patients may have recurrent buccal space abscesses.