Head and Neck Imaging

Masticator space

1. Anatomy

space containing the masticatory muscles (medial and lateral pterygoid muscle, masseter muscle, temporal muscle); these muscles attach to the ascending ramus and angle of the mandible. The nerve of the masticator space is the mandibular nerve (third branch of the trigeminal nerve); it supplies the motor innervation of the masticatory muscles and provides via the inferior alveolar nerve sensation to the mandibular teeth, gums and lower lip/chin region. The part of the masticator space below the level of the zygomatic arch is sometimes called the infratemporal fossa, and the part above it the temporal fossa.

2. Pathology

A lesion within the masticator space is usually sited in the ascending ramus or angle of the mandible, or within the masticatory muscles; the lesion is anterolateral to the parapharyngeal space. Trismus (masticatory muscle spasm causing inability to open the mouth) is a common symptom in masticator space pathology, restricting the clinician's examination of this area, and making the imaging findings of major importance.

Common lesions include:

  • abscess, usually of dental origin (Fig.1); this may be accompanied by mandibular osteomyelitis.

  • squamous cell carcinoma head and neck, either by direct invasion from the oropharynx (see oropharynx cancer) or from the retromolar trigone, or by perineural tumour spread head and neck along the inferior alveolar nerve and mandibular nerve.

  • sarcoma, of either muscular or bony origin (see chondrosarcoma head and neck, osteosarcoma head and neck, rhabdomyosarcoma head and neck).

  • non Hodgkin lymphoma head and neck manifestation (non-Hodgkin lymphoma, head and neck manifestation (VI:2), Fig. 2).

    RH

    • To view high resolution images,
    please register first.

    Click  here to register.

    Already registered? Enter your e-mail in the window below.
    Re-register

    Fig.1

    Axial contrast-enhanced CT images showing abscess formation in the left masticator space (a, arrow), originating from a dental (molar) abscess (b, bone window, arrowhead). The abscess spreads along the mandible to the left submandibular space (c) and submental space (d), spreading again superiorly into the right submandibular space (arrowhead in c), causing cellulitis in the right parapharyngeal space (arrowhead in a).
    Masticator space, Fig.1 (a)
    Masticator space, Fig.1 (b)
    Masticator space, Fig.1 (c)
    Masticator space, Fig.1 (d)