eRadiograph Volume 7: Imaging of Oral Cavity | Page 11

- posteriorly by the insertion of anterior tonsillar pillar on tongue
- superiorly by the undersurface of oral tongue.
Floor is made by the mylohyoid muscle and sublingual space.
The mylohyoid arises from the mylohyoid ridge, running along the entire inner surface
of the mandible, from the symphysis to the 3 molar. The anterior and middle fibres of
the mylohyoid insert into a midline fibrous raphe, and the posterior fibres insert into
the hyoid bone. The median raphe extends from the hyoid bone posteriorly to the
symphysis mentii anteriorly. This forms a U shaped sling best seen on coronal images.
The geniohyoid and genioglossus lie internal to the mylohyoid and the anterior belly of
digastric external to the mylohyoid. The mylohyoid cleaves the lower oral cavity
into sublingual and submandibular spaces. The sublingual space is superior and
medial to the mylohyoid while submandibular space is inferior and lateral to
mylohyoid. The posterior border of mylohyoid is free, allowing communication
between sublingual and submandibular spaces. The submandibular gland, which lies
below the mylohyoid, wraps around the free edge of the mylohyoid. Its superficial
portion lies in the submandibular space, and its deep lobe lies above the mylohyoid in
the sublingual space.

The submandibular space contains:
• The anterior belly of digastric
• The superficial portion of submandibular gland
• Facial vein/artery
• Inferior loop of 12th cranial nerve
• Submandibular/ submental lymph nodes.
The hyoglossus, styloglossus and palatoglossus muscles divide the sublingual space
into medial and lateral compartments. This is an important surgical landmark as the
hypoglossal, lingual nerves and whartons duct lies lateral to the muscles and the
lingual artery and vein medial. Whartons duct arises from the deep portion of the
submandibular gland, which lies in the sublingual space and runs anteriorly in close
contact with the hypoglossal and lingual nerves to open just lateral to the frenulum of
the tongue.
The digastric muscle has 2 bellies, an anterior and a posterior. The anterior belly arises
from the digastric fossa on the inner surface of the mandible. The posterior belly arises
from the digastric fossa on the inner surface of the mastoid process of temporal bone.
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Imaging of Oral Cavity

The sublingual space contains the:
• Anterior extension of hyoglossus
• Lingual nerve
• Cranial nerves 9/12
• Lingual artery and vein
• Sublingual glands and duct
• Deep portion of submandibular gland/ duct.