Muscles of tongue

The muscles of the tongue, with the exception of palatoglossus, are supplied by the hypoglossal nerve. Palatoglossus is supplied via the pharyngeal plexus.

Ans. A i.e. Facial nerve supplies fungi from papillae; B i.e. Glossopharyngeal nerve supplies circumvallate papillae ; C i.e. Genioglossus is the safety muscle

–           anterior 2/3 of tongue is supplied by chorda tympani branch of facial nerveQ (carrying taste sensation) & lingual nerveQ (carrying general sensation); posterior 1/3 of tongue is supplied by glossopharyngeal nerveQ (carrying taste & general sensation both); and posterior most tongue in the region of valleculae is supplied by internal laryngeal branch of vagus nerveQ

–                  Except palatoglossus (extrinsic muscle) all muscles of tongue (i.e. all intrinsic muscles eg bilateral superior & inferior longitudinal, transverse & vertical and 3 pairs of extrinsic muscles i.e. genioglossus, hypoglossus & styloglossus/ chondroglossus) are supplied by lzypoglossal nerveQ

Hypoglossal nerve has only motor (but no sensory) supply to tongueQ, so injury to it can not lead to loss of taste or general sensationQ. Injury to hypoglossal nerve present with pure motor tongue features such as ipsilateral muscular

• Genioglossus is the fan-shaped extrinsic tongue muscle that forms the majority of the body of the tongue. Its origin is the mental spine of the mandible and its insertions are the hyoid bone and the dorsum of the tongue. 
• Contraction of the genioglossus stabilizes and enlarges the portion of the upper airway that is most vulnerable to collapse. A relaxation of the genioglossus and geniohyoideus muscles, especially during REM sleep, is implicated in Obstructive Sleep Apnea (OSA.)
• Peripheral damage to the hypoglossal nerve can result in deviation of the tongue to the damaged side