eRadiograph Volume 7: Imaging of Oral Cavity | Page 324

Malignant Neoplasms
Squamous cell carcinoma occurring in the floor of mouth is usually a spread from
tongue carcinoma. Less than 10% of all salivary gland tumors arise in the sublingual,
minor salivary glands however most of these are malignant. The most common is
adenocystic carcinoma a slow growing neoplasm however with a high propensity for
perineural spread muco epidermoid CA second most common malignant neoplasm.

Submandibular
and Sublingual Space

Denervation Muscle Atrophy
Disruption of neural supply to muscles or muscle groups results in atrophy of the
muscles with fatty infiltration. On imaging the muscles on the contralateral side will
appear hypertrophic and may mimic a neoplasm. The key to the diagnosis fatty
atrophy of the muscles. The hypoglossal nerve innervates the intrinsic/extrinsic muscles
of the tongue. The mandibular nerve innervates muscles of mastication, tensor
tympani, tensor palatani, anterior belly of digastric and mylohyoid muscles. Injury to
these nerves results in muscle atrophy with fatty infiltration. An injury to only
mylohyoid branch of mandibular nerve will result in atrophy of anterior belly of
diagastric and mylohyoid muscles.

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