Oral Cavity & Palate Lecture 2024 PDF

Oral cavity and palate Nutrition module Anatomy Department Parts of oral cavity:  1- Vestibule:  2- Mouth cavity proper  Vestibule of the mouth the part of the cavity outside teeth and gums Boundaries: Externally by the lips& cheeks, internally by the teet...

Oral cavity and palate Nutrition module Anatomy Department Parts of oral cavity:  1- Vestibule:  2- Mouth cavity proper  Vestibule of the mouth the part of the cavity outside teeth and gums Boundaries: Externally by the lips& cheeks, internally by the teeth and gums. Receive the opening of the parotid ducts opposite the 2nd upper molar tooth.  Mouth cavity proper Boundaries:  Anterior &Sides: alveolar arches of both upper and lower jaws.  Posterior: communicates with oropharynx (via oropharyngeal isthmus).  Roof: the hard and soft palate.  Floor: # tongue, sublingual fold (mucous membrane over the sublingual salivary gland) deep part of sunmandibular & mylohyoid muscle...  Lips Fleshy fibers of orbicularis oris ms. covered by skin externally & lined by mucous membrane. Nerve supply: #Upper lip: Buccal branch of fascial N. #Lower lip: Marginal mandibular of fascial N. Arterial supply: #Upper lip: Superior labial of fascial A. #Lower lip: Inferior labial of fascial A. Nerve& Arterial supply of lips  Cheek Form the side of the vestibule, limited anteriorly by nasolabial groove. Consist of: # Skin #Buccal pad of fat. # Buccopharyngeal fascia. # Buccinator ms. # Mucous membrane. Nerve supply of cheek  Skin & mucosa supplied by Buccal branch of mandibular nerve. -Buccinator ms supplied by Buccal branch of facial nerve.  Tongue Definition: mass of skeletal (striated) muscles covered by mucous membrane. Lies in floor of oral cavity. suspended from the following structure: - Soft palate: by palatoglossus ms. - Styloid process: by styloglossus ms. - Mandible: by genioglossus ms. Hyoid bone: by hyoglossus ms.  tongue  Apex (tip of tongue) & margins lies just behind the teeth & gums.  Root of tongue, posterior part that receive extrinsic muscles connecting tongue with mandibule, hyoid & styloid process.  Superior Surface (dorsum of tongue)  Inferior surface  Inferior Surface of tongue:  Shows triad of folds (1median &2 lateral) with bilateral (V A N) in between:  - Lingual frenulum: midline fold connects this surface with the floor of mouth. On each side of its posterior end lies a sublingual papilla.  - Deep lingual vein: appears as a dark blue line lateral to frenulum.  - Lingual artery-  lingual nerve.  Fimbriated fold: lateral to lateral to V A N.  Lower surface of tongue 1- Frenulum linguae. 2- Deep lingual vein. 3- Plica fimbriata.  Upper surface of tongue - The superior surface shows v- shaped sulcus (sulcus terminalis )that marks the junction between anterior 2/3(oral part) and post. 1/3 of tongue (pharyngeal part). - Pit at the apex of sulcus terminalis called foramen caecum. - The 2 parts differ embryologically, so they are differ in the nerve supply…….. Oral part of the tongue:  Anterior 2/3 of tongue, it contains all types of papillae filliform, fugiform and vallate.  Innervated by lingual nerve (general sensation) & chorda tympani (taste sensation) Pharyngeal part of the tongue:  - The post. 1/3 that lies behind the terminal sulcus.  - Has no papilla, no taste buds.  - It is irregular due to presence of nodules of lymphoid tissue in the submucosa (lingual tonsils).  - Its posterior part called base of tongue connected to epiglottis by median & lateral glosso-epiglotic folds that form boundary of vallecula.  - Innervated by glossopharyngeal nerve (all sensations)  Lingual tonsil Mass of lymphoid tissue embedded in dorsal surface of the pharyngeal part. Glosso-epiglottic folds  Intrinsic ms of the tongue Superior longitudinal ms. Inferior longitudinal ms. Transverse ms. Vertical ms. Action: alter the shape of the tongue to help speech, mastication and swallowing. Extrinsic Muscles of tongue: Extrinsic Muscles of tongue:  Genioglossus ms Triangular ms in the floor of the mouth. Origin: upper genial tubercle of inner aspect of symphysis menti. Insertion: whole lower surface of the tongue. Action: 2 ms draw the tongue forwards. 1 ms deviate it to the opposite side. Nerve supply: hypoglssal N.  Hyoglossus ms Origin: whole length of the greater horn of hyoid bone. Insertion: side of the tongue. Action: depress the tongue. Nerve supply: hypoglssal N.  Styloglossus ms Origin: styloid process. Insertion: side of the tongue. Action: draw the tongue upward and backward. Nerve supply: hypoglssal N.  Palatoglossus ms Origin: palatine aponeurosis. Insertion: side of tongue at junction of ant 2/3 and post 1/3. Action: draw root of tongue uoward, close the oropharynx. Nerve supply: cranial root of accessory n..  EXTRINSIC MUSCLES Muscle Origin Insertion Action 1-Palatoglossus Lower surface of Posterior 1/3 of the side Pulls tongue upwards in 1st palatine aponeurosis of tongue stage of swallowing 2-Hyoglossus Body and greater horn Posterior ½ of the side Depresses the tongue EXTRINSIC MUSCLES of the hyoid bone of the tongue 3-Styloglossus Tip of the styloid process Along whole length of Retracts the protruded the side of the tongue tongue 4-Genioglossus Upper genial tubercle of -Along the whole The two muscles pull the the mandible length of under surface tongue forwards of tongue.  Nerves of the tongue Motor nerve: all ms of the tongue supplied by hypoglossal n except palatoglossus n, by cranial root of accessory n. Sensory nerves: Anterior 2/3: general sensation: lingual n. taste sensation: chorda tympani n Posterior 1/3: both general and taste sensation by glossopharyngeal n Palate  Palate Septum separating oral cavity from nasal cavity. Hard palate bony septum separating oral cavity from nasal cavity. Soft palate it is a fold of mucous membrane filled with muscle extending  posteriorly from hard palate. It lies between nasopharynx and oropharynx.  Soft palate It consists of aponeurosis attached to posterior border of hard palate, and 5 palatine ms. Its median free posterior border conical in shape, called uvula. Function:1- during respiration.? 2- during swallowing.?  Soft palate Two folds extend laterally and downwards from the soft palate: 1- Palatoglossal fold: anterior fold, containing the palatoglossus ms, and attached to the side of the tongue. 2- Palatopharyngeal fold: posterior fold, containing the palatopharyngus ms, and attached to the side of the pharynx, and thyroid cartilage.  Muscles of soft palate  1- Tensor palati: from base of the skull and lateral aspect of Eustachian tube to the  upper surface of palatine aponeurosis. Action: Tensor for soft palate, open the auditory tube. Nerve supply: the mandibular N. 2- Levator palati: from petrous part of temporal bone and Medial side of of auditory tube to the palatine aponeurosis. Action: elevate the soft palate to close the pharyngeal isthmus during the swallowing. Nerve supply: cranial root of accessory N.  Muscles of soft palate 3- Palatoglossus ms: raise the mucous membrane forming palatoglossus arch which bounds the oropharyngeal isthmus. inside the palatoglossal fold. Action: the 2 ms pull the tongue upward, and close the oropharyngeal isthmus. Nerve supply: cranial root of accessory N. 4- palatopharyneus ms: inside the palatopharyngeal fold. Action: the 2 ms shorten the wall of the pharynx during the swallowing. Nerve supply: cranial root of accessory N. 5- Musculus uvulae: 2 ms close to each other, one on each side of the midline. From the palatine aponeurosis, to the mucous membrane of the uvula. Action: pull the uvula towards its side. Nerve supply: cranial root of accessory N.  Nerve supply of palate Motor supply: All palatine muscles are supplied by cranial accessory through the vagus( by its pharyngeal branch (via pharyngeal plexus) except Tensor Palati which by Mandibular nerve (5th C.N.). Sensory:  hard palate - Lesser, Greater &sphenopalatine (nasopalatine) branches of pterygopalatine ganglion to.  - soft palate Tonsillar branches of Glossopharyngeal nerve to.(9th C.N.)  Function of palate:  Relax during respiration to allow air to pass from nasopharynx to oropharynx.  elevation of soft palate to posterior wall of pharynx closing the pharyngeal isthmus, this occurs during swallowing to prevent regurge of food to nasal cavity. Thanks GOD