Anatomy of the Oral Cavity PDF

Anatomy of the oral cavity By Dr. Shilan Hussein Objectives ► By the end of the lecture the students should be able to: ► Describe the oral cavity, boundaries and contents. ► Describe the anatomy of the Tongue and its muscles, nerve supply. The Digestive System in the Head and Neck ► The...

Anatomy of the oral cavity By Dr. Shilan Hussein Objectives ► By the end of the lecture the students should be able to: ► Describe the oral cavity, boundaries and contents. ► Describe the anatomy of the Tongue and its muscles, nerve supply. The Digestive System in the Head and Neck ► The Mouth ► The Lips The lips are two fleshy folds that surround the oral orifice. ► They are covered on the outside by skin and are lined on the inside by mucous membrane. ► The substance of the lips is made up by the orbicularis oris muscle. ► The philtrum is the shallow vertical groove seen in the midline on the outer surface of the upper lip O O angle between uni skinandmucusmembrane o h The Mouth Cavity ► The mouth extends from the lips to the pharynx. ► The entrance into the pharynx, the oropharyngeal isthmus, is formed on each side by the palatoglossal fold . ► o The mouth is divided into the vestibule and the mouth cavity proper. If 3rdmolar ► Vestibule ► The vestibule lies between the lips and the cheeks externally and the gums and the teeth internally. ► This slitlike space communicates with the exterior through the oral fissure between the lips. ► When the jaws are closed, it communicates with the mouth proper behind the third molar tooth on each side. e teeth isthespacebetweencheeksand ► The vestibule is limited above and below by the reflection of the mucous membrane from the lips and cheeks to the gums. ► The lateral wall of the vestibule is formed by the cheek, which is made up by the buccinator muscle and is lined with mucous membrane. e O O O onlysublingual has multiple opening ► The tone of the buccinator muscle and that of the muscles of the lips keeps the walls of the vestibule in contact with one another. ► The duct of the parotid salivary gland opens on a small papilla into the vestibule opposite the upper second molar tooth. ► Mouth Proper ► The mouth proper has a roof and a floor. ► Roof of Mouth ► The roof of the mouth is formed by the hard palate in front and the soft palate behind ► Floor of Mouth ► The floor is formed largely by the anterior two thirds of the tongue and by the reflection of the mucous membrane from the sides of the tongue to the gum of the mandible ► A fold of mucous membrane called the frenulum of the tongue connects the undersurface of the tongue in the midline to the floor of the mouth. ► The submandibular duct of the submandibular gland opens onto the floor of the mouth on the summit of a small papilla on either side of the frenulum of the tongue. ► ► The sublingual gland projects up into the mouth, producing a low fold of mucous membrane, the sublingual fold. Numerous ducts of the gland open on the summit of the fold. __ ► Mucous Membrane of the Mouth ► In the vestibule, the mucous membrane is tethered to the buccinator muscle by elastic fibers in the submucosa that prevent redundant folds of mucous membrane from being bitten between the teeth when the jaws are closed. ► The mucous membrane of the gingiva, or gum, is strongly attached to the alveolar periosteum. nerve supply ► Sensory Innervation of the Mouth palatinforamen greater incisive foramen ► Roof: The greater palatine and nasopalatine nerves from the maxillary division of the trigeminal nerve. ► Floor: The lingual nerve (common sensation), a branch of the mandibular division of the trigeminal nerve. ► The taste fibers travel in the chorda tympani nerve, a branch of the facial nerve. E mandibular buccal nerve facial forthecheeks sensory motorforthemusclesof expression ► Cheek: ► The buccal nerve, a branch of the mandibular division of the trigeminal nerve which is sensory. ► (the buccinator muscle is innervated by the buccal branch of the facial nerve which is motor) The Tongue ► The tongue is a mass of striated muscle covered with mucous membrane. ► The muscles attach the tongue to the styloid process and the soft palate above and to the mandible and the hyoid bone below. ► The tongue is divided into right and left halves by a median fibrous septum. ► Mucous Membrane of the Tongue ► The mucous membrane of the upper surface of the tongue can be divided into anterior and posterior parts by a V-shaped sulcus, the sulcus terminalis. ► The apex of the sulcus projects backward and is marked by a small pit, the foramen cecum. ► The sulcus serves to divide the tongue into the anterior two thirds, or oral part, and the posterior third, or pharyngeal part. e ► The foramen cecum is an embryologic remnant and marks the site of the upper end of the thyroglossal duct. ► oftastebuds Three types of papillae are present on the upper surface of the anterior two thirds of the tongue: ► the filiform papillae, ► the fungiform papillae, ► and the vallate papillae. FE ► The mucous membrane covering the posterior third of the tongue is devoid of papillae but has an irregular surface , caused by the presence of underlying lymph nodules, the lingual tonsil. of called aggregation nodes lymph lingualtonsil T.I.ve e i Ma sulcusterminalis ► The mucous membrane on the inferior surface of the tongue is reflected from the tongue to the floor of the mouth. ► In the midline anteriorly, the undersurface of the tongue is connected to the floor of the mouth by a fold of mucous membrane, the frenulum of the tongue. ► On the lateral side of the frenulum, the deep lingual vein can be seen through the mucous membrane. IS ► Muscles of the Tongue ► The muscles of the tongue are divided into two types: ► intrinsic and extrinsic. Tattachment hasno tobone 8 ► ► Intrinsic Muscles e These muscles are confined to the tongue and are not attached to bone. ► They consist of longitudinal, transverse, and vertical fibers. ► Nerve supply: Hypoglossal nerve ► nervetsupplyt Icranial supplies Action: Alter the shape of the tongue. muscles the ► ► Extrinsic Muscles These muscles are attached to bones and the soft palate. They are the genioglossus, the hyoglossus, the styloglossus, and the atextonguee palatoglossus. ► ► ► Ea.ge EfueFidprocessFngue Nerve supply: Hypoglossal nerve The origin, insertion, nerve supply, and action of the tongue muscles are summarized in Table 11.8 ► Blood Supply ► The lingual artery, the tonsillar branch of the facial artery, and the ascending pharyngeal artery supply the tongue. ofthemarbrannerofexte.no ianotidantery ► IFIII If The veins drain into the internal jugular vein. ► Lymph Drainage ► Tip: Submental lymph nodes in ► Sides of the anterior two thirds: Submandibular and deep cervical lymph nodes. ► submentaltriangI Posterior third: Deep cervical lymph nodes motor Hypoglossalnerve ► Sensory Innervation ► Anterior two thirds: Lingual nerve branch of mandibular division of trigeminal nerve (general sensation) and chorda tympani branch of the facial nerve (taste). ► Posterior third: Glossopharyngeal nerve (general sensation and taste) ► important not β Movements of the Tongue ► Protrusion: The genioglossus muscles on both sides acting together. ► Retraction: Styloglossus and hyoglossus muscles on both sides acting together. ► Depression: Hyoglossus muscles on both sides acting together ► Retraction and elevation of the posterior third: Styloglossus and palatoglossus muscles on both sides acting together ► Shape changes: Intrinsic muscles styloidprocess musclets 3 attachment stylohyoid Stylopharangens a phalangealtonsil salpingopharangeal openingofthe fold auditory tube enticaland for im transvers B ua nfevioulongitudmy 1 4 p'an jade palatoglossus sublingual hyoglossus sabad gudartey hypostyle The Palate & salivary glands By Dr. Shilan Hussein Objectives ► By the end of the lecture the students should be able to : ► Describe the anatomy of the palate, its parts. ► The nerve supply and the blood supply of the palate. ► Types of tonsils and their location. ► The 3 salivary glands, their anatomical location, their ducts openings. The Palate ► The palate forms the roof of the mouth and the floor of the nasal cavity. ► It is divided into two parts: the hard palate in front and the soft palate behind. ► Hard Palate ► The hard palate is formed by the palatine processes of the maxillae and the horizontal plates of the palatine bones . ► It is continuous behind with the soft palate. ► Soft Palate ► The soft palate is a mobile fold attached to the posterior border of the hard palate. ► Its free posterior border presents in the midline a conical projection called the uvula. is a ► The soft palate is continuous at the sides with the lateral wall of the pharynx 6 E ► The soft palate is composed of mucous membrane, palatine aponeurosis, and muscles. ► 1. The mucous membrane covers the upper and lower surfaces of the soft palate. ► 2. The palatine aponeurosis is a fibrous sheet attached to the posterior border of the hard palate. ► It is the expanded tendon of the tensor veli palatini muscle. ► 3. The muscles of the soft palate are the tensor veli palatini, the levator veli palatini, the palatoglossus, the palatopharyngeus, and the musculus uvulae. ► Nerve Supply of the Palate ► The greater and lesser palatine nerves from the maxillary division of the trigeminal nerve enter the palate through the greater and lesser palatine foramina. ► The nasopalatine nerve, also a branch of the maxillary nerve, enters the front of the hard palate through the incisive foramen. ► The glossopharyngeal nerve also supplies the soft palate. ► Blood Supply of the Palate ► The greater palatine branch of the maxillary artery, the ascending palatine branch of the facial artery, and the ascending pharyngeal artery. e Its p c artery ► The palatoglossal arch is a fold of mucous membrane containing the palatoglossus muscle, which extends from the soft palate to the side of the tongue. ► The palatoglossal arch marks where the mouth becomes the pharynx. so Formdbypalatoglossusmuscle ► The palatopharyngeal arch is a fold of mucous membrane behind the palatoglossal arch, that runs downward and laterally to join the pharyngeal wall. ► The muscle contained within the fold is the palatopharyngeus muscle. etween two arches ► The palatine tonsils, ► which are masses of lymphoid tissue, are located between the palatoglossal and palatopharyngeal arches thage The Salivary Glands E ► The parotid gland ► is the largest salivary gland and is composed mostly of serous acini. ► It lies in a deep hollow below the external auditory meatus, behind the ramus of the mandible , and in front of the sternocleidomastoid muscle. ► The facial nerve divides the gland into superficial and deep lobes. 1 2 3 passingthroughparotidgland 8 I I IF ► The parotid duct ► emerges from the anterior border of the gland and passes forward over the lateral surface of the masseter. ► It enters the vestibule of the mouth upon a small papilla opposite the upper second molar tooth. ÉÉnator ► Parotid Salivary Gland and Lesions of the Facial Nerve ► The parotid salivary gland consists essentially of superficial and deep parts, and the important facial nerve lies in the interval between these parts. ► A benign parotid neoplasm rarely, if ever, causes facial palsy. ► A malignant tumor of the parotid is usually highly invasive and quickly involves the facial nerve, causing unilateral facial paralysis. ► The submandibular gland ► consists of a mixture of serous and mucous acini (Mixed). ► It lies beneath the lower border of the body of the mandible and is divided into superficial and deep parts by the mylohyoid muscle f O O ► The deep part of the gland lies beneath the mucous membrane of the mouth on the side of the tongue. ► The submandibular duct emerges from the anterior end of the deep part of the gland and runs forward beneath the mucous membrane of the mouth. ► It opens into the mouth on a small papilla, which is situated at the side of the frenulum of the tongue. ► The sublingual gland ► lies beneath the mucous membrane (sublingual fold) of the floor of the mouth, close to the frenulum of the tongue. ► It has both serous and mucous acini, with the latter predominating. The sublingual ducts (8 to 20 in number) open into the mouth on the summit of the sublingual fold. F