Actions of tongue muscles Inferior Longitudinal: moves tip up & down Superior Longitudinal: moves tip up & down Transverse: narrows & lengthens tongue Vertical: flattens & depresses tongue Genioglossus: Prevents tongue from falling back Styloglossus: Pulls tongue up & back Palatoglossus: Pulls tongue back Hyoglossus: Depresses tongue
Nerve Supply of Tongue *** except palatoglossus which is supplied by pharyngeal plexus Anterior 2/3Posterior 1/3 SensoryLingualGlossopharyngeal MotorHypoglossal *** TasteChorda tympaniGlossopharyngeal
Lingual taste buds sit on lateral borders of raised papillae. They are classified as: Fungiform: at tip & sides of tongue Circumvallate: just in front of terminal sulcus Foliate: at posterior lateral margins of tongue Filiform: centre of tongue, have no taste buds
Lower Limit of Nasopharynx Lower border of soft palate or Junction b/w hard & soft palate Oropharynx Tip of epiglottis or Body of hyoid bone or Base of vallecula HypopharynxLower border of cricoid or Lower border of C6 vertebra
Nasopharyngeal Isthmus Separates nasopharynx from oropharynx Bounded anteriorly by soft palate & posteriorly by mucosal ridge on nasopharyngeal wall called Passavant’s ridge (due to palatopharyngeus) Closure of this isthmus prevents nasal regurgitation & nasal intonation
Waldeyer's tonsillar ring Vertically oriented, sub-epithelial lymphoid tissue ring located in pharynx, thought to function as a barrier to infection in first few years of life. Named after nineteenth century German anatomist Heinrich Wilhelm Gottfried von Waldeyer-Hartz.
Triangular weak area between thyropharyngeus & cricopharyngeus part of inferior constrictor Mucosa herniates through it to form hypo- pharyngeal pouch (Zenker’s diverticulum) Perforation occurs here during forceful oesophagoscopy (gateway of tears)
Mucous coat 1. Epithelium: non-keratinizing stratified sqamous 2. Lamina propria: loose areolar tissue with lymphoid aggregates 3. Muscularis mucosae: produces local movement of mucosa & helps in drainage of gland secretions
Mucous coat Pink, smooth, protective oesophageal mucosa leads to red, mamillated, secretory gastric mucosa across Z (zigzag) line at 38-40 cm from incisors. Higher Z line seen in Barret’s esophagus.
Fibrous coat (adventitia) Layer of loose, supportive fibrous tissue Conducts major vessels & nerves longitudinally A serosa formed by visceral peritoneum replaces adventitia of intra-abdominal segment of oesophagus