eRadiograph Volume 7: Imaging of Oral Cavity | Page 322

auditory meatus to the angle of the mandible, including the parotid gland.
Second branchial cleft cyst may present anywhere in the parapharyngeal space
superficial to the sternocleidomastoid muscle deep to platysma seen typically dorsal to
submandibular gland, lateral to carotid space and anteromedial to
sternocleidomastoid muscle.
2nd Branchial cleft cysts displace submandibular gland anteriorly,
sternocleidomastoid posterolaterally carotid and jugular posteromedially.
Inflammatory Lesions
The most common cause for inflammation/infections involving the floor of the mouth
are dental infections – these are usually from premolar teeth or first molar tooth. The
relationship of the mandibular teeth to the myelohyoid ridge determines which space
will be involved by infection. The apices of the second and third molar lie below the
mylohyoid ridge this apical infection of these will result in extension to submandibular
space. The first molar root apices are located above the mylohyoid ridge thus infection
will involve primarily the sublingual space. Other causes of infection are penetrating
trauma, obstructing submandibular duct calculi, intravenous drug use, noninfectious
causes such as autoimmune disorders and sarcoidosis.
Inflammation/infection manifests as cellulitis/abscess.

Ludwigs angina is a severe form of cellulitis often secondary to dental infection. The
inflammation spreads contiguously involving the sublingual and submandibular
spaces bilaterally sparing the glandular structures. The role of imaging in Ludwig
angina is to demonstrate the extent, any airway compromise, presence of any gas
forming organisms, underlying dental infection, osteomyelitis or the presence of an
abscess. Early recognition and treatment are vital as the mortality 10%.
On imaging the process is seen to involve both sublingual and submandibular spaces,
frequently bilateral. There is usually associated gangrenous or serosanguinous
phelgmon but no frank pus, involving connective tissue, fascia, muscle but sparing of
the glandular structures. The spread of infection is by contiguity and not by lymphatics.
Usually a history of dental extraction is present 2 – 4 days prior to onset.

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Submandibular
and Sublingual Space

Cellulitis is seen as edematous changes in the subcutaneous fat seen as alteration of
fat density/intensity and soft tissue stranding in the subcutaneous fat. The overlying
skin is thickened as it is oedematous. There may be enhancement of adjacent facial
planes/muscles.