Masticator space
The masticator space is one of the deep compartments of the head and neck.
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Gross anatomy
The masticator space are paired suprahyoid cervical spaces on each side of the face. Each space is enveloped by the superficial (investing) layer of the deep cervical fascia.
The superficial layer of deep cervical fascia splits into two at the lower border of the mandible, the inner layer running deep to the medial pterygoid muscle and attaches to the skull base medial to foramen ovale and the outer layer covering masseter and temporalis muscles and attaches to the parietal calvaria superiorly.
Contents
- muscles of mastication
- ramus and body of mandible
- mandibular division of the trigeminal nerve (Vc)
- enters the masticator space via the foramen ovale 1
- inferior alveolar nerve
- inferior alveolar artery and vein
Boundaries and relations
- anteriorly: buccal space
- posterolaterally: parotid space
- medially: parapharyngeal space
Communications
Masticator space malignancy can spread perineurally via the mandibular division of the trigeminal nerve into the middle cranial fossa.
Radiographic appearance
Ultrasound
- limited use when imaging the masticator space
- masseter muscles, zygomatic arch, outer cortex of the ramus of mandible and suprazygomatic segment of temporal muscle can all be visualized
- limited visualization of a number of important structures 3:
- pterygoid muscles
- pterygoid venous plexus
- mandibular branch of the trigeminal nerve
CT
- best modality for detecting bony erosion in the cortex of the mandible and is excellent for characterizing tumor matrix mineralization
- abscess in the masticator space shows up as a fluid collection with peripheral rim enhancement whereas a phlegmon shows low density edematous tissue without peripheral enhancement 2
- schwannoma appears as a well-circumscribed fusiform mass with extension through the foramen ovale and is higher in attenuation that adjacent muscle and shows contrast enhancement 5
MRI
MRI better characterizes soft tissue invasion by tumors and perineural tumor spread 2:
- schwannoma demonstrates intermediate signal on T1-WI and hyperintensity on T2-WI with contrast enhancement
- neurofibroma generally show heterogeneity on T2-WI and heterogeneous contrast enhancement 5
- locally invasive carcinoma from the nasopharynx or oral cavity demonstrate intermediate-to-high signal on T2-WI and low signal on T1-WI, with or without bone destruction and perineural spread; lymphadenopathy is common 8
Nuclear medicine
- PET/CT with FDG tracer can be used to detect metastatic disease and to differentiate recurrent tumors from post-radiation change 2
Related pathology
- odontogenic abscess
- osteomyelitis
- direct spread of squamous cell carcinoma
- lymphoma
- minor salivary gland tumors
- muscle sarcoma
- bone sarcoma
- osteoradionecrosis
- schwannoma
- neurofibroma
- benign masseteric hypertrophy
- accessory parotid tissue
Related Radiopaedia articles
Anatomy: Head and neck
- skeleton of the head and neck
-
cranial vault
- scalp (mnemonic)
-
sutures
- calvarial
- facial
- frontozygomatic suture
- frontomaxillary suture
- frontolacrimal suture
- frontonasal suture
- temporozygomatic suture
- zygomaticomaxillary suture
- parietotemporal suture (parietomastoid suture)
- occipitotemporal suture (occipitomastoid suture)
- sphenofrontal suture
- sphenozygomatic suture
- spheno-occipital suture (not a true suture)
- lacrimomaxillary suture
- nasomaxillary suture
- internasal suture
- basal/internal
- skull landmarks
- frontal bone
- temporal bone
- parietal bone
- occipital bone
- skull base (foramina)
-
facial bones
- midline single bones
- paired bilateral bones
- cervical spine
- hyoid bone
- laryngeal cartilages
-
cranial vault
- muscles of the head and neck
- muscles of the tongue (mnemonic)
- muscles of mastication
- muscles of facial expression
- muscles of the middle ear
- orbital muscles
- muscles of the soft palate
- pharyngeal muscles
- suprahyoid muscles
- infrahyoid muscles
- intrinsic muscles of the larynx
- muscles of the neck
-
deep spaces of the neck
- anterior cervical space
- buccal space
- carotid space
- danger space
- deep cervical fascia
- infratemporal fossa
- masticator space
- parapharyngeal space
- parotid space
- pharyngeal (superficial) mucosal space
- perivertebral space
- posterior cervical space
- pterygopalatine fossa
- retropharyngeal space
- suprasternal space (of Burns)
- visceral space
- surgical triangles of the neck
- orbit
- ear
- paranasal sinuses
-
nose
-
external nose
-
nasal cartilages
- greater alar cartilage
- lesser alar cartilage
- septal cartilage
- lateral cartilage
- nasal vestibule
- anterior naris
- nasal ala
- nasal sill
- columella
-
nasal cartilages
- nasal septum
- pyriform aperture
- nasal cavity
- nasal concha
- Kiesselbach plexus
- Schneiderian epithelium
-
external nose
- oral cavity
- pharynx
- larynx
- viscera of the neck
- blood supply of the head and neck
-
arterial supply
-
common carotid artery
- carotid body
- carotid bifurcation
- subclavian artery
- variants
-
common carotid artery
- venous drainage
-
arterial supply
- innervation of the head and neck
-
cranial nerves
- olfactory nerve (CN I)
- optic nerve (CN II)
- oculomotor nerve (CN III)
- trochlear nerve (CN IV)
-
trigeminal nerve (mnemonic) (CN V)
- ophthalmic division
- maxillary division
- mandibular division
- abducens nerve (CN VI)
- facial nerve (CN VII)
- vestibulocochlear nerve (CN VIII)
- glossopharyngeal nerve (CN IX)
- vagus nerve (CN X)
- (spinal) accessory nerve (CN XI)
- hypoglossal nerve (CN XII)
- parasympathetic ganglia of the head and neck
- greater occipital nerve
-
cervical plexus
- muscular branches
- longus capitis
- longus colli
- scalenes
- geniohyoid
- thyrohyoid
-
ansa cervicalis
- omohyoid (superior and inferior bellies separately)
- sternothyroid
- sternohyoid
- phrenic nerve
- contribution to the accessory nerve (CN XI)
- cutaneous branches
- muscular branches
- brachial plexus
- pharyngeal plexus
-
cranial nerves
- lymphatic drainage of the head and neck