The Salivary Glands

Salivary glands The salivary glands are the parotid, submandibular, and sublingual glands , and small accessory glands, scattered over the palate, lips, cheeks, tonsils, and tongue. Saliva is the clear, tasteless, odorless viscid fluid, secreted by these glands and the mucous glands of the oral cavity: Keeps the mucous membrane of the mouth moist. Lubricates the food during mastication. Begins the digestion of starches. Serves as an intrinsic mouthwash. Plays significant roles in the prevention of tooth decay and in the ability to taste

Parotid Gland 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.

Parotid Gland Wedge shape Superior margin – glenoid process Anterior margin – facial process Accessory gland anteriorly with its duct Enclosed by the investing fascia

Parotid Gland Parotid duct 5 cm long and passes forward across the masseter anteriorlly about a fingerbreadth below the zygomatic arch. then pierces the buccinator muscle to enter the mouth opposite the upper second molar tooth as small papilla. Oblique passage act as valve, preventing inflation during blowing

Parotid gland

Parotid Gland Structures within the gland from lateral to medial Facial N Retromandibular V External carotid artery L.N.

Parotid Gland Blood supply : EX.CA Venous drainage: Retromandibular veins.

Nerve supply The great auricular nerve: from C2 and C3 spinal nerves, innervates the parotid sheath and the overlying skin. Sympathetic fibers are derived from the cervical ganglia through the external carotid nerve plexus on the external carotid artery . The vasomotor activity of these fibers may reduce secretion from the gland. Sensory nerve fibers pass to the gland through the great auricular and auriculotemporal nerves.

Nerve supply The parasympathetic component of the glossopharyngeal nerve supplies presynpatic secretory fibers to the otic ganglion. The postsynaptic parasympathetic fibers are conveyed from the ganglion to the gland by the auriculotemporal nerve . Stimulation of the parasympathetic fibers produces saliva.

Parotid Gland A malignant tumor of the parotid may involves the facial nerve, causing unilateral facial paralysis. Infection: by ducts or blood stream ( mumps) Frey’s syndrome : production of sweat instead of saliva due to penetrating injury to nerves Parotidectomy

Submandibular Gland The submandibular gland consists of a mixture of serous and mucous acini. It lies beneath the lower border of the body of the mandible divides into superficial and deep parts by the mylohyoid muscle.

Submandibular Gland 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

Submandibular Gland Passing from lateral to medial, the lingual nerve loops under the duct that runs anteriorly

Submandibular gland From submental arteries Veins with arteries

Submandibular Gland Nerve Supply Parasympathetic secretomotor supply is from the facial nerve to lingual nerve via the chorda tympani, which synapse with postsynaptic neurons in the submandibular ganglion . vasoconstrictive postsynaptic sympathetic fibers from the superior cervical ganglion

Submandibular Salivary Gland 1- Calculus Formation The submandibular salivary gland is a common site of calculus formation. 2- Enlargement of the Submandibular Lymph Nodes and Swelling of the Submandibular Salivary Gland The submandibular lymph nodes are commonly enlarged .

Sublingual Gland The sublingual gland lies beneath the mucous membrane of the floor of the mouth, close to the frenulum of the tongue . The sublingual ducts (8 to 20 in number) open into the mouth on the summit of the sublingual fold

Sublingual Gland Nerve Supply Parasympathetic secretomotor supply is from the facial nerve via the chorda tympani, and the submandibular ganglion.

Muscles of mastication 1- Masseter muscle 2- Temporalis muscle 3- Medial pterygoid 4- Lateral pterygoid

Masseter muscle O : Z arch I : ramus of mandible N : V , mandibular branch A : raise mandible

Temporalis muscle O: temporal bone and fascia (cover) I: mandible N: deep temporal nerve, mandibular b, V A: elevate and retract mandible

Lateral pterygoid O: sphenoid and lateral pterygoid plate I: neck of mandible N: mandibular b V A: protract mandible, rotatory movement as chowing

Lateral Pterygoid – 2 heads Upper head (sphenomeniscus part) O: from infratemporal surface of greater wing of sphenoided I: articular disc (meniscus) of TMJ and upper part of neck of mandible

Superficial Head O: tuberosity of maxilla I (of both heads): medial suface of angel and ramus of mandible (as high as mandibular foramen) A (of both heads): elevates and protracts jaw

Lower head (main part) O: lateral surface of lateral pterygoid plate I: Pterygoid fovea of neck of mandible A (of both heads): protract (chief one) and depresses jaw

Medial pterygoid O: maxilla and lat. Pterygoid plate I: angle of mandible N: mand, V A: elevate mandible, protract

Deep Head (main one) O: medial surface of lateral pterygoid plate and pyramidal process of palatine bone

Temporal and infratemporal fossa Temporal area: from superior temporal line to Z arch Beneath the base of skull inferior to Z arch b/w pharynx and ramus of the mandible Communicate deep to arch

Temporal fossa The floor of the temporal fossa is formed by parts of the four bones that form the pterion. The fan-shaped temporal muscle arises from the bony floor and the overlying temporal fascia which forms the roof of the temporal fossa. This tough fascia covers the temporal muscle, attaching superiorly to the superior temporal line. Inferiorly, the fascia splits into two layers, which attach to the lateral and medial surfaces of the zygomatic arch.

Temporal fossa Contents; 1- temporalis muscle 2- deep temporal nerve (ant, mand, V) 3- auriculotemporal nerve ( post, mand, V) 4- superficial temporal artery

Infratemporal fossa Laterally: the ramus of the mandible. Medially: the lateral pterygoid plate. Anteriorly: the posterior aspect of the maxilla. Posteriorly: the tympanic plate and the mastoid and styloid processes of the temporal bone. Superiorly: the inferior (infratemporal) surface of the greater wing of the sphenoid. Inferiorly: where the medial pterygoid muscle attaches to the mandible near its angle.

Infrtemporal fossa Contents: Lateral and medial pterygoid Branches of the mandibular nerve Chorda tympani Maxillary artery Otic ganglion Pterygoid venous plexus

Maxillary Artery The maxillary artery runs forward medial to the neck of the mandible , and enters the pterygopalatine fossa of the skull. Branches supply the upper and the lower jaws, the muscles of mastication, the nose, the palate, and the meninges inside the skull. In fossa gives Inferior alveolar artery Middle meningeal artery Muscular branches

Pterygoid venous plexus maxillary vein With pterygoid muscles Drains to maxillary vein With superficial temporal vein forming retromandibular vein

Otic Ganglion is a parasympathetic ganglion that is located medial to the mandibular nerve just below the skull inferior to the foramen ovale it is adherent to the nerve to the medial pterygoid muscle. The preganglionic fibers originate in the glossopharyngeal nerve The postganglionic secretomotor fibers reach the parotid salivary gland via the auriculotemporal nerve.

Infratemporal fossa Corda tympani Facial nerve branch Join lingual nerve Carries secretomotor parasympathetic fibers to submandibular amd subligual glands Taste fibers anterio 2/3 tongue and floor

Trigeminal Nerve The trigeminal nerve is the largest cranial nerve It leaves the pons as a small motor root and a large sensory root passes forward, out of the posterior cranial fossa, to reach the apex of the petrous part of the temporal bone in the middle cranial fossa. the large sensory root expands to form the trigeminal ganglion The trigeminal ganglion lies within a pouch of dura mater called the trigeminal cave. The motor root of the trigeminal nerve is situated below the sensory ganglion and is completely separate from it.

Ophthalmic Nerve (V1) The ophthalmic nerve is purely sensory It runs forward in the lateral wall of the cavernous sinus in the middle cranial fossa divides into three branches, the lacrimal, frontal, and nasociliary nerves, which enter the orbital cavity through the superior orbital fissure.

Ophthalmic Nerve (V1) Branches 1- The lacrimal nerve : enters the lacrimal gland and gives branches to the conjunctiva and the skin of the upper eyelid and the gland 2- The frontal nerve : divides into the supraorbital and supratrochlear nerves , supply the frontal air sinus and the skin of the forehead and the scalp.

Ophthalmic Nerve (V1) Branches 3- The nasociliary nerve crosses the optic nerve , continues as the anterior ethmoid nerve , enter the nasal cavity. supplies the skin of the tip of the nose with the external nasal nerve. Its branches include the following: Long ciliary nerves that contain sympathetic fibers to the dilator pupillae muscle and sensory fibers to the cornea Infratrochlear nerve that supplies the skin of the eyelids Posterior ethmoidal nerve that is sensory to the ethmoid and sphenoid sinuses

Maxillary Nerve (V2 The maxillary nerve arises from the trigeminal ganglion in the middle cranial fossa. It passes forward in the lateral wall of the cavernous sinus and leaves the skull through the foramen rotundum

Maxillary Nerve (V2 enter the orbit through the inferior orbital fissure It then continues as the infraorbital nerve in the infraorbital groove, and it emerges on the face through the infraorbital foramen. It gives sensory fibers to the skin of the face and the side of the nose.

Maxillary Nerve (V2 It gives sensory fibers to the skin of the face and the side of the nose.

Maxillary Nerve (V2 Branches Meningeal branches Zygomatic branch : supply the skin of the face. Posterior superior alveolar nerve which supplies the maxillary sinus , the upper molar teeth and adjoining parts of the gum and the cheek

Maxillary Nerve (V2 Branches Middle superior alveolar nerve , which supplies the maxillary sinus , the upper premolar teeth, the gums, and the cheek Anterior superior alveolar nerve , which supplies the maxillary sinus , the upper canine and the incisor teeth

Mandibular Nerve (V3) The mandibular nerve is both motor and sensory , The sensory root leaves the skull through the foramen ovale to enter the infratemporal fossa. The motor root of the trigeminal nerve also leaves the skull through the foramen ovale and joins the sensory root to form the trunk of the mandibular nerve, and then divides into a small anterior and a large posterior division .

Mandibular Nerve (V3) Branches From the Main Trunk of the Mandibular Nerve 1- Meningeal branch 2- Nerve to the medial pterygoid muscle, which supplies medial pterygoid, and the tensor veli palatini muscle.

Mandibular Nerve (V3) Branches From the Anterior Division of the Mandibular Nerve 1- Masseteric nerve 2- Deep temporal nerves 3- Nerve to the lateral pterygoid muscle 4- Buccal nerve to the skin and the mucous membrane of the cheek . the only sensory branch of the anterior division of the mandibular nerve.

Mandibular Nerve (V3) Branches From the Posterior Division of the Mandibular Nerve 1- Auriculotemporal nerve, which supplies the skin of the auricle , the external auditory meatus, the temporomandibular joint, and the scalp. 2- Lingual nerve : crosses the submandibular duct. it supplies the mucous membrane of the anterior two thirds of the tongue and the floor of the mouth. -

Mandibular Nerve (V3) Branches From the Posterior Division of the Mandibular Nerve 3- Inferior alveolar nerve : which enters the mandibular canal to supply the teeth of the lower jaw and emerges through the mental foramen (mental nerve) to supply the skin of the chin , the mylohyoid muscle and the anterior belly of the digastric muscle 4- The branches of the posterior division of the mandibular nerve are sensory (except the nerve to the mylohyoid muscle).