Anatomy and pathology of the masticator space

Abstract

ObjectiveThis article reviews and illustrates the anatomy and pathology of the masticator space (MS).BackgroundPathology of the masticator space includes inflammatory conditions, vascular lesions, and tumours. Intrinsic tumours of this space can be benign and malignant, and they may arise from the mandibular ramus, the third division of the trigeminal nerve, or the mastication muscles. Malignant tumours may appear well defined and confined by the masticator fascia, without imaging signs of aggressive extension into neighbouring soft tissues. Secondary invasion of the masticator space can also occur with tumours of the nasopharynx, oropharynx, oral cavity, and parotid glands. Perineural tumour spread (PNS), especially along the trigeminal nerve, can also occur with masticator space malignancies.ConclusionMasses of the MS are difficult to evaluate clinically, and computed tomographic (CT) and magnetic resonance (MR) images are essential for the diagnosis and characterisation of these lesions. Malignant tumours may appear well defined and confined by the fascia. Thus, when a mass is identified, a biopsy should be done promptly. PNS may occur in tumours involving the MS and its recognition on imaging studies is essential to plan the appropriate treatment.Teaching points• Differentiating between intrinsic and extrinsic lesions is essential to the differential diagnosis• Infections of the MS may cross the fascia and mimic neoplasms on imaging studies• Malignant tumours may show no aggressive signs, such as bone erosion or violation of the fascia• Perineural spread (PNS) is often clinically silent and frequently missed at imaging and leads to tumour recurrence

Penetrating foreign body in the masticator space with injury to the internal maxillary artery: a surgical challenge

“…MS pathology includes inflammatory conditions of odontogenic origin, lymphovascular malformations, as well as benign and malignant tumours. 1,2 Preoperatively, IMA injuries can be recognised by clinical and radiographic means. Physical examination often reveals an expanding and pulsatile haematoma over the temporomandibular joint or cheek region and malocclusion with an associated history of facial trauma.…”

Computed tomography and magnetic resonance imaging of lesions at masticator space

“…1). Anteriorly, the fascia attaches in the body of the mandible at the level of the oblique line; posteriorly, the fascia connects to the posterior aspect of the ramus of the mandible [1][2][3][4].…”

“…This space also contains the ramus and the posterior body of the mandible, the mandibular division of the trigeminal nerve (V3) [2], and the inferior alveolar vein and artery and branches of the internal maxillary artery [3][4][5][6] (Fig. 1).…”

“…Patients with masticator space lesions usually present with trismus, facial swelling, and pain [1]. Patients may not open the mouth, and the physical examination is rather limited [2,3]. Therefore, imaging techniques are crucial in order to provide an accurate diagnosis of lesions involving the masticator space.…”

“…The clinician needs to know the nature of the lesion in the masticator space and its localization and extension into the adjacent spaces. These findings are essential for deciding therapeutic modalities as well as for appropriate planning of surgery or radiation therapy [3][4][5]. Table 1 shows the lesions of the masticator space.…”