There are many causes of tongue numbness, including systemic disease, lingual nerve injury, and linguopharyngeal nerve injury.
Tongue numbness and abnormal sensation can be caused by diabetes, medications, neuritis, cerebrovascular disease, cervical spine disease, vascular disease, or trauma, etc. Numbness cannot be treated symptomatically, but rather for the cause.
The lingual nerve, one of the branches of the mandibular nerve, is a sensory nerve that runs anterior to the inferior alveolar nerve and downward in an arch along the outside of the lingual muscle of the hyoid bone to the tip of the tongue. It is distributed in the anterior 2/3 of the mucosa of the tongue and receives the general sensation of the mucosa.
The lingual branch of the glossopharyngeal nerve is distributed in the posterior 1/3 of the mucosa of the tongue and the taste buds, and is the general sensory and taste sensation there. Therefore, damage to the nerve causes loss of sensation in the area where it is distributed, which manifests as numbness of the tongue.
The lingual nerve is superficially located on the distal mesiolingual side of the mandibular third molar and is covered only by mucosa, which can cause injury to the nerve during gingival flap removal or floor of mouth surgery of mandibular impacted wisdom teeth.
Most injuries to the linguopharyngeal nerve occur with firearm injuries, mandibular fractures, and tumor compression. The exact cause of the numbness of the tongue needs to be examined to know and treated for the cause.