Tongue External features- • Root • Tip • Body- dorsum or superior surface & inferior surface Root-attached to the mandible & soft palate above and to the hyoid bone below. Tip- anterior free end & lies behind the upper incisor teeth. Dorsum-oral part or ant 2/3rd & pharyngeal part or post 1/3rd part, V shaped groove- suclus terminalis, median pit- foramen caecum. Oral part or papillary part of the tongue- foliate papillae 4 to 5 vertical folds in front of the palatoglossal arch, rough superior surface and covered with papillae, inferior surface smooth mucous membrane which shows the median fold- frenulum lingulae, plica fimbriata Pharyngeal part or lymphoid part of the tongue- lies behind the palatoglossal arches and the sulcus terminalis. It forms the base of the tongue forming the anterior wall of the oropharynx. Devoid of the papillae & has many lymphoid follicles. Lingual tonsil & mucous gland are also present. Posterior most part- connected to epiglottis by 3folds of mucous membrane- median glossoepiglottic fold, rt and lt glossoepiglottic folds. Vallecula
Tongue Papillae of the tongue • Vallate or circumvallate papillae- 1-2 mm in diameter & 8-12in number • Fungiform papillae- numerous near the tip & margins of the tongue • Filiform papillae or conical papillae- presulcal area of the dorsum of the tongue and gives the velvety appearance
Tongue Muscles of the tongue- Intrinsic muscles- • Superior longitudinal • Inferior longitudinal • Transverse • Vertical
Tongue Extrinsic muscles- • Genioglossus • Hyoglossus • Styloglossus • palatoglossus
Tongue Arterial supply- • Lingual artery • Root of tongue is supplied by the tonsillar & ascending pharyngeal arteries Venous drainage- Deep lingual vein- lingual vein- CFV or IJV
Tongue Lymphatic drainage- • Tip of the tongue-submental lymph nodes • Rt and lt halves of the remaining ant 2/3rd- submandibular nodes • Posterior 1/3rd- bilaterally- jugulo-omohyoid nodes and these are know as the lymph nodes of the tongue
Tongue Nerve supply- Motor nerves- all the intrinsic & extrinsic muscles expect the palatoglossus are supplied by the hypoglossal nerve. Palatoglossus supplied by the cranial part of the accessory nerve through pharyngeal plexus Sensory nerves- Lingual nerve for general sensation and chorda tympani for the taste of ant 2/3rd of the tongue except vallate papillae. Glossopharyngeal nerve is both general sensory and taste for the post 1/3rd of the tongue including circumvallate papillae Posteriormost part of the tongue is supplied by the vagus nerve through the internal laryngeal nerve.