Dr. Mohamed Ahmad Taha Mousa Assistant Professor of Anatomy and Embryology

Objectives a. Identify different components of the oral cavity b. Describe the relationships of salivary glands to its surrounding structures

Mouth Lips: They are two folds surrounding the oral orifice. - It is formed by orbicularis oris muscle covered by mucous membrane. Mouth cavity: It extends from the lips to the pharynx. - It is divided into the vestibule and the mouth cavity proper. A. Vestibule: It lies between: - Lips and cheeks  Externally. - Gums and teeth  Internally. - The cheek is made up by the buccinator muscle and is lined with mucous membrane. - The duct of the parotid gland: It opens into the vestibule of the mouth opposite the upper 2nd molar tooth.

B. Mouth cavity proper: It has roof and floor. - Roof of mouth: It is formed by the hard palate in front and the soft palate behind - Floor of mouth: It is formed by the anterior 2/3 of the tongue. - The duct of the submandibular gland opens onto the floor of the mouth on either side of frenulum of the tongue. - The sublingual gland projects up into the floor of the mouth producing the sublingual fold. - Numerous ducts of the gland open on the summit of the fold. Sensory innervations of the mouth: Roof: Greater palatine and nasopalatine nerves from maxillary division of the trigeminal nerve.

Floor: A- General sensation by lingual nerve (branch from mandibular division of the trigeminal N). B- Taste sensation by the chorda tympani nerve (branch from the facial N). Cheek: Buccal nerve (branch from mandibular division of the trigeminal nerve). Teeth: Deciduous teeth: There are 20 deciduous teeth. Permanent teeth: There are 32 permanent teeth. Tongue: It is a mass of striated muscle covered by mucous membrane. Mucous membrane of the tongue: It is divided by a V-shaped sulcus (sulcus terminalis) into anterior 2/3 (oral part containing papillae) and posterior 1/3 (pharyngeal part containing lingual tonsils). - The apex of the V shaped is the foramen cecum

Muscles of the tongue: It divided into two types A- Intrinsic muscles: They consists of longitudinal, transverse and vertical fibers. B- Extrinsic muscles: It includes genioglossus, hyoglossus, styloglossus and palatoglossus. - Nerve supply: All of intrinsic and extrinsic muscles are supplied by hypoglossal nerve except palatoglossus muscle is supplied by pharyngeal plexus. Blood supply: - Lingual artery, facial artery, and ascending pharyngeal artery. - The veins drain into the internal jugular vein. Lymph drainage: Submental, Submandibular and deep cervical lymph nodes Sensory innervations: - Anterior 2/3: General sensation by lingual nerve - Taste sensation by chorda tympani nerve. - Posterior 1/3: Glossopharyngeal nerve (general and taste sensation).

The Palate - It forms the roof of the mouth and the floor of the nasal cavity. - It is divided into two parts: A. Hard palate: It is formed by: - Palatine processes of the maxillae. - Horizontal plates of the palatine bones. B. Soft palate: It 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. - It is composed of muscles, palatine aponeurosis and covered by mucous membrane. Mucous membrane: It covers the upper and lower surfaces of the soft palate. Palatine aponeurosis: It is a fibrous sheet attached to the posterior border of the hard palate.

Muscles of the soft palate: It includes tensor veli palatini, levator veli palatini, palatoglossus, palatopharyngeus and musculus uvulae. Nerve supply of the palate: Sensory: - Greater, lesser palatine and nasopalatine nerves (from the maxillary division of the trigeminal nerve). - Glossopharyngeal nerve also supplies the soft palate. Motor: - All muscles are supplied by cranial part of the accessory nerve via the pharyngeal plexus except tensor veli palatini supplied by mandibular nerve. Blood supply of the palate: - Greater palatine branch of the maxillary artery. - Ascending palatine branch of the facial artery. - Ascending pharyngeal artery Lymph drainage: Deep cervical lymph nodes.

Parotid gland Definition: It is the largest salivary gland and it is composed mostly of serous acini. Site: It lies in a deep hollow below the external auditory meatus, behind the ramus of the mandible and in front of sternocleidomastoid muscle. Parts of the glands: The facial nerve divides the gland into superficial and deep lobes. Parotid duct: - It emerges from the anterior border of the gland and passes over the lateral surface of masseter. - It opens in the vestibule of the mouth opposite the upper 2nd molar tooth.

Relation of parotid gland: It is pyramidal form. - The concave superior surface (base): It is related to external auditory meatus, temporomandibular joint and auriculotemporal nerve. - Apex: It overlaps the posterior belly of digastric - Superficial surface: It is covered by skin and superficial fascia containing great auricular nerve and superficial parotid lymph nodes). - Anteromedial surface: It is related to masseter muscle, posterior border of the ramus of the mandible and medial pterygoid muscle. - Posteromedial surface: It is related to: - Mastoid process, sternocleidomastoid and posterior belly of the digastric. - Styloid process and its associated muscles. - Carotid sheath containing (internal carotid artery, vagus nerve and internal jugular vein) and it is separated from the gland by the styloid process.

Structures within the parotid gland: 1. External carotid artery: It is the deepest structures in the gland and it divides into maxillary and superficial temporal artery. 2. Retromandibular vein: It is formed by union of the maxillary and superficial temporal veins. - It is superficial to the external carotid artery. 3. Facial nerve: It is the most superficial. Nerve supply:- Parasympathetic secretomotor supply from the glossopharyngeal nerve  tympanic branch  lesser petrosal nerve  relay in otic ganglion  auriculotemporal nerve - Sensory supply: By auriculotemporal nerve. Blood supply: It is supplied by the external carotid artery. - Veins drain into the external jugular vein.

Submandibular salivary gland Structure: It is consists of a mixture of serous and mucous acini. Site: - It is situated in the digastric triangle. Relation : -Inferior surface: It is covered by skin, superficial fascia containing (platysma, facial vein and cervical branch of the facial nerve) and deep fascia. - Lateral surface: It is related to submandibular fossa on the body of the mandible. - Facial artery grooves its posterosuperior part then it lies between the lateral surface of the gland and mandible. - Medial surface: It is related to: - Mylohyoid muscle, mylohyoid nerve and vessels - Hyoglossus, lingual nerve, submandibular ganglion and hypoglossal nerve. - Styloglossus, stylohyoid ligament and glossopharyngeal nerve.

Submandibular duct: It emerges from the anterior end of the deep part of the gland then it opens into the mouth at both sides of the frenulum of the tongue. Arterial supply: It is supplied by facial and lingual arteries. Lymphatic drainage: It drain into the deep cervical lymph nodes Nerve supply: - Parasympathetic secretomotor supply is from the facial nerve via the chorda tympani and the submandibular ganglion. The postganglionic fibers pass directly to the gland - General sensation by lingual nerve.

Sublingual gland Structure: It has both serous and mucous acini, with the latter predominating. Site: It lies under the mucous membrane (sublingual fold) of the floor of the mouth, close to the frenulum of the tongue. Sublingual ducts (8 to 20 in number): It opens into the mouth on the summit of the sublingual fold. Arterial supply: It is supplied by facial and lingual arteries. Nerve supply: - Parasympathetic secretomotor supply is from the facial nerve via the chorda tympani  relay in the submandibular ganglion  Postganglionic fibers pass directly to the gland.

Thank you