oral medicine & Pathology

masticator space infections : Imaging , clinical findings , pathology , treatment , epidemiology


  masticator space infections



  •  The majority of masticator space infections are secondary to odontogenic infections.
  • These patients are typically adolescents or adults with poor oral h ygiene. Occasionally, masticator space infection is secondary to malignant otitis externa often seen in diabetics or immunologically compromised patients.

Clinical Findings

  •  Patients with masticator space abscess typically present with pain, fever, and trismus.
  • The diagnosis of dental abscess or malignant otitis externa is usually evident from the clinical history and associated signs and symptoms.
  • Trismus associated with masticator space infection often hampers the examination of the oral cavity or oropharynx.
  • In addition, malignant otitis externa with temporomandibular joint extension may further aggravate trismus


  •  The vast majority of masticator space abscesses due to odontogenic disease consist of mixed infection.
  • Masticator space abscess may also be due to malignant otitis externa with the most common organism being Pseudomona


  •  The treatment for masticator space infection involves controlling the infection of the primary site.
  • Spreading cellulitis requires only antibiotic therapy, and surgery is indicated only when pus formation ensues.
  • If mandibular or external auditory canal osteomyelitis is present, subperiosteal drainage will be required.
  • Multiple abscesses in multiple spaces may necessitate complex drainage procedures.

Imaging Findings


  •  Inflammation of the masticator space causes swelling of one or a combination of the following muscles: medial and lateral pterygoids and temporalis and masseter muscles.
  • There is usually moderate to good contrast enhancement.
  • Mandibular or temporal bone erosion is best seen on CT images acquired with bone algorithm.
  • A masticator space abscess is characterized by a well-defined low attenuation mass that may have an enhancing rim


  • On fat suppressed, contrast-enhanced MR images, there is strong contrast enhancement of the involved muscles.
  • A diagnosis of abscess formation is made when a mass with areas of no enhancement is noted.
  • T2-weighted MR images typically show high signal intensities

Imaging Pearls

Bone algorithms need to be evaluated for evidence of odontogenic disease in all cases of abscesses involving the masticator space .

• When a masticator space abscess is secondary to malignant otitis externa, it is important to document the full extent of the skull base and temporal bone involvement.

  • This may require thin sections in both axial and coronal planes using bone algorithms.





 masticator space infections radiology

ــــــــــــــــــــ ⒹⒺⓃⓉⒶⓁⓈⒸⒾⒺⓝⓒⒺ ــــــــــــــــــــ