NASOPHARYNX, PNS & SALIVARY GLANDS
DR. SRINIVAS RAJKUMAR THIRAVIARAJ
Why is this subdivision
The primary tumors in each of these areas have different routes of
• nodal dissemination
• Cuboidal chamber
• Begins at Posterior Choana
• Continues into Oropharynx via pharyngeal isthmus
• posterior nasal cavity
• Lower clivus, upper cervical
• spine, and prevertebral
• Divided from the oropharynx
• by a horizontal line drawn
• along the hard and soft
• Level I
• below mylohyoid muscle and above the lower margin of the hyoid bone
• anterior to the posterior border of the submandibular glands
• level Ia – submental nodes – between the anterior bellies of the digastric muscles
• level Ib – submandibular nodes – posterolateral to the anterior belly of the digastric muscles
• Level II
• internal jugular (deep cervical) chain
• base of skull to inferior border of hyoid bone
• anterior to the posterior border of sternocleidomastoid (SCM) muscle
• posterior to the posterior border of the submandibular glands
• level IIa – anterior, lateral, or medial to the vein or posterior to the internal jugular vein and inseparable from it
• level IIb – posterior to the internal jugular vein and have a fat plane separating the nodes and the vein
• between CCAs, below superior aspect of manubrium
• Level III
• internal jugular (deep cervical) chain
• lower margin of hyoid to lower margin of cricoid cartilage
• anterior to the posterior border of SCM
• lateral to the medial margin of the common carotid artery (CCA)/internal carotid artery (ICA)
• Level IV
• internal jugular (deep cervical) chain
• lower margin of cricoid cartilage to level of the clavicle
• anterior and medial to an oblique line drawn through the posterior edge of the sternocleidomastoid muscle and the posterolateral edge of the anterior scalene muscle 4
• lateral to the medial margin of the CCA
• Level V
• posterior triangle (spinal accessory) nodes
• level Va – superior half, posterior to levels II and III (between base of skull and inferior border of cricoid cartilage)
• level Vb – inferior half, posterior to level IV (between inferior border of cricoid cartilage and the level of clavicles)
• Level VI
• prelaryngeal/pretracheal/Delphian node
• anterior to visceral space
• from inferior margin of hyoid bone to manubrium
• anterior to of levels III and IV
• Level VII
• superior mediastinal nodes
• triangular hole between sphenoid, apex of petrous temporal and basilar part of occipital.
• The artery of pterygoid canal, the nerve of pterygoid canal and some venous drainage pass through the foramen lacerum.
• Foramen Ovale
• Posterior part of the sphenoid bone, Posterolateral to the foramen rotundum.
• Otic ganglion,
• V3( Mandibular nerve )
• Accessory meningeal artery,
• Lesser petrosal nerve,
• Emissary veins)
• Carcinoma of the nasopharynx frequently arises from the lateral wall, with a predilection for the fossa of Rosenmuller
• Anteriorly into the nasal fossa,
• Posterolaterally beyond the pharyngobasilar fascia to involve the parapharyngeal and the carotid spaces
• Laterally to the pterygoid muscles,
• Posteriorly to the prevertebral muscles
• inferiorly to the oropharynx
• Superiorly, bony erosion of the skull base involving
• The floor of the sphenoid sinus,
• Apex of petrous bone
• Basal foramina.
• ? Intracranially via foramen lacerum
• High frequency of perineural spread along the maxillary division (V2) and the mandibular division (V3) of the trigeminal nerve with subsequent intracranial extension through the foramen rotundum and foramen ovale
Adjacent soft tissue
Bony erosion/paranasal sinus
• Before the era of CT – plain radiography
• The classic 5 views of NPC that Ho described consist of lateral, submentovertical, occipitosubmental, 25° occipitomental, and occipitomaxillary views
• T1 Attenuation = Metastasis
PARA NASAL SINUSES
• the Ethmoid air cells
• separated from the orbital cavity by a thin, porous bone, the lamina papyracea, and from the anterior cranial fossa by a portion of the frontal bone, the fovea ethmoidalis.
• They are in close proximity to the optic nerves laterally and the optic chiasm posteriorly.
• The middle ethmoid cells open directly into the middle meatus.
• The anterior cells may drain indirectly into the middle meatus via the infundibulum.
• The posterior cells open directly into the superior meatus.
• The various radiographic positions used to study paranasal sinuses are:
• 1. Occipito-mental view (Water’s view)
• 2. Occipital-frontal view (Caldwel view)
• 3. Submento-vertical position (Hirtz position)
• 4. Lateral view
• 5. Oblique view 39 Degrees oblique (Rhese position)
• The maxillary sinuses are the largest of the paranasal sinuses.
• They are pyramid-shaped cavities located in the maxillae.
• The lateral walls of the nasal cavity form the base and the roofs correspond to the orbital floors, which contain the infraorbital canals.
• The floors of the maxillary sinuses are composed of the alveolar processes.
• The apices extend toward and frequently into the zygomatic bones.
• Secretions drain by mucociliary action into the middle meatus via the hiatus semilunaris through an aperture near the roof of the maxillary sinus.
• Ohngren’s line is a theoretic plane dividing each maxillary sinus into the suprastructure and infrastructure; it is defined by connecting the medial canthus with the angle of the mandible.
• The sphenoid bone forms a midline inner cavity that communicates with the nasal cavity through an aperture in its anterior wall
• It is directly apposed superiorly to the pituitary gland and optic chiasm, laterally to the cavernous sinuses, anteriorly to the ethmoid sinuses and nasal cavity, and inferiorly to the nasopharynx.
• The paired, typically asymmetric frontal sinuses are located between the inner and outer tables of the frontal bone.
• They are anterior to the anterior cranial fossa, superior to the sphenoid and ethmoid sinuses, and superomedial to the orbits. They usually communicate with the middle meatus of the nasal cavity.
• Nasal vestibule carcinomas can spread by direct invasion of the upper lip, gingivolabial sulcus, premaxilla (early events), or nasal cavity (late event)
• Vertical invasion may result in septal (membranous or cartilaginous) perforation or alar cartilage destruction.
• Lymphatic spread from nasal vestibule carcinomas is usually to the ipsilateral facial (buccinator and mandibular) and submandibular nodes.
Nasal Cavity and Ethmoid Sinuses
• The pattern of contiguous spread of carcinomas varies with the location of the primary lesion.
• Tumors arising in the upper nasal cavity and ethmoid cells can extend to the orbit through the thin lamina papyracea and to the anterior cranial fossa via the cribriform plate, or they may grow through the nasal bone to the subcutaneous tissue and skin.
• Lateral wall primaries invade the maxillary antrum, ethmoid cells, orbit, pterygopalatine fossa, and nasopharynx.
• Primaries of the floor and lower septum may invade the palate and maxillary antrum.
• Perineural extension (typically involving branches of the trigeminal nerve) is seen most frequently with adenoid cystic carcinomas.
• Lymphatic spread of nasal cavity primaries is uncommon, although spread to retropharyngeal and cervical lymph nodes is possible
• The pattern of spread of maxillary sinus cancers varies with the site of origin.
• Suprastructure tumors extend into the nasal cavity, ethmoid cells, orbit, pterygopalatine fossa, infratemporal fossa, and base of skull.
• Invasion of these structures gives lesions of the suprastructure a poorer prognosis.
• Treatment is associated with greater morbidity as a consequence of craniofacial resection or radiation of intracranial and ocular structures
• . Infrastructure tumors often infiltrate the palate, alveolar process, gingivobuccal sulcus, soft tissue of the cheek, nasal cavity, masseter muscle, pterygopalatine space, and pterygoid fossa.
• The maxillary sinuses are have a limited lymphatic supply
• Correspondingly low incidence of lymphadenopathy at diagnosis (Ipsilateral subdigastric and submandibular nodes are involved most frequently.
• Hematogenous spread is uncommon.
• Asymptomatic plaques or nodules, often with crusting and scabbing.
• Advanced lesions – pain, bleeding, or ulceration.
• Nasal cavity tumors present with symptoms and signs of nasal polyps (e.g., chronic unilateral discharge, ulcer, obstruction, anterior headache, and intermittent epistaxis), hence delaying the diagnosis.
• Additional symptoms and signs develop as the lesion enlarges: medial orbital mass, proptosis, expansion of the nasal bridge, diplopia resulting from invasion of the orbit, epiphora due to obstruction of the nasolacrimal duct, anomaly of smell or anosmia from involvement of the olfactory region, or frontal headache due to extension through the cribriform plate.
• Central/facial head-aches and referred pain to the nasal or retrobulbar region,
• a subcutaneous mass at the inner canthus,
• nasal obstruction and discharge,
• diplopia, and proptosis.
• Diagnsosis mostly made in advanced stages
• facial swelling, pain, or
• paresthesia of the cheek induced by disease extension to the premaxillary region,
• epistaxis, nasal discharge and obstruction related to tumor spread to the nasal cavity
• The gland has four surfaces superficial or lateral,superior, anteromedial and posteromedial.
• The gland has three borders anterior, medial and posterior. The Parotid gland has two ends: superior end in the form of small superior surface and an inferior end (apex).
• (1) Superficial or lateral relations: The gland is related superficially to the skin. Superficial fascia, superficial lamina of investing layer of deep cervical fascia and Great auricular nerve (anterior ramus of C2 and C3)
• (2) Anteromedial relations: The gland is related anteromedially to the mandibular ramus, masseter and medial pterygoid muscles. A part of the gland may extend between the ramus and medial pterygoid as the pterygoid process. Branches of facial nerve and parotid duct emerge through this surface.
• (3) Posteromedial relations: The gland is related posteromedially to mastoid process of temporal bone with its attached Sternocleidomastoid and digastric muscles, styloid process of temporal bone with its three attached muscles (Stylohyoid, Stylopharyngeus and Styloglossus) and carotid sheath with its contained neurovasculature (Internal Carotid artery, Internal Jugular vein, 9th, 10th, 11th and 12th cranial nerves)
• (4) Medial relations: The parotid gland comes into contact with the superior pharyngyeal constrictor muscle at the medial border where the anteromedial and posteromedial surfaces meet. Hence there is a need to examine the fauces in parotitis
Parotid Gland Anatomy Summary
• Superficial to and partly behind the ramus of the mandible and covers the masseter muscle.
• Superficially, it overlaps the posterior part of the muscle and largely fills the space between the ramus of the mandible and the anterior border of the sternocleidomastoid muscle.
• One or more isthmi that wrap around the branches of the facial nerve connect the superficial and deep lobes of the gland.
• The nerve enters the deep surface of the gland as a single trunk, passing posterolateral to the styloid process.
• It usually leaves the gland as five or more branches, emerging at the anterior, upper, and lower borders of the gland.
• The facial nerve runs superficial to the main blood vessels that traverse the gland but is interwoven within the glandular tissue and its ducts.
• The parotid gland contains an extensive lymphatic capillary plexus, many aggregates of lymphocytic cells, and numerous intraglandular lymph nodes in the superficial lobe
• Lymphatics drain from more lateral areas on the face, including parts of the eyelids, diagonally downward and posteriorly toward the parotid gland, as do the lymphatics from the frontal region of the scalp.
• Superficially and more deeply, are parotid nodes.
• Drain downward along the retromandibular vein to empty in part into the superficial lymphatics and nodes along the outer surface of the sternocleidomastoid muscle and in part into upper nodes of the deep cervical chain.
• Lymphatics from the parietal region of the scalp drain partly to the parotid nodes in front of the ear and partly to the retroauricular nodes in back of the ear, which, in turn, drain into upper deep cervical nodes
• Entirely autonomic.
• Postganglionic sympathetic fibers from superior cervical sympathetic ganglion reach the gland as periarterial nerve plexuses around the external carotid artery and their function is mainly vasoconstriction.
• The cell bodies of the preganglionic sympathetics usually lie in the lateral horns of upper thoracic spinal segments.
• Preganglionic parasympathetic fibers leave the brain stem from inferior salivatory nucleus in the glossopharyngeal nerve (cranial nerve IX) and then through its tympanic and then the lesser petrosal branch pass into the otic ganglion. There, they synapse with postganglionic fibers which reach the gland by hitch-hiking via the auriculotemporal nerve, a branch of the mandibular nerve.
• Parotid gland salivation is ultimately caused by the glossopharyngeal nerve
• The paired submandibular glands or submaxillary glands are major salivary glands located beneath the floor of the mouth.
• They weigh about 15 grams and produce around 60-67% of the total volume of saliva.
• Fills the triangle between the two bellies of the digastric and the lower border of the mandible and extends upward deep to the mandible.
• It lies partly on the lower surface of the mylohyoid and partly behind the muscle against the lateral surface of the muscle of the tongue, the hypoglossus.
• The submandibular gland has a larger superficial part, or body, and a smaller deep process.
• The inferior surface is adjacent to the submandibular lymph nodes, and the deep process of the submandibular gland lies between the mylohyoid laterally and the hyoglossus medially, and between the lingual nerve above and the hypoglossal nerve below .
• Rich lymphatic capillary network lies in the interstitial spaces of the gland.
• From the lateral and superior portions of the gland, lymph flows to the prevascular or preglandular submandibular lymph nodes.
• The posterior portion of the gland gives rise to one or two lymphatic trunks, which follow the facial artery and go directly to the anterior subdigastric nodes of the internal jugular chain .
• Arterial Supply – facial and lingual arteries.
• Venous Drainage – lingual and facial veins.
• Lymphatics – The submandibular nodes lie in close proximity to the gland, or within its structure. Lymph flows from this region to the upper deep cervical nodes (level II).
• Lymph will usually travel to upper deep cervical nodes, including the jugulo-omohyoid node.
• The submandibular ganglion is the source of neural supply to the submandibular gland. This small ganglion is associated with the lingual nerve as it passes anteriorly along the floor the mouth. Parasympathetic fibres arrive via the chorda tympani, a branch of the facial nerve VII. Sympathetic fibres are derived from the facial artery plexus.
• General sensory nerves arrive from the lingual nerve (V3).
• This smallest of the three major salivary glands
• Lies between the mucous membrane of the floor of the mouth above and the mylohyoid muscle below, the mandible laterally, and the genioglossus muscles of the tongue medially .
• The sublingual gland drains either to the submandibular lymph nodes or more posteriorly into the deep internal jugular chain between the digastric and omohyoid muscles. Rarely, the lymphatics of the sublingual gland drain into a submental node or supraomohyoid jugular node
• Arterial Supply
• The sublingual branch of the lingual artery and submental branch of the facial artery contribute to the supply of the sublingual gland.
• Venous Drainage
• Either accompanying sublingual veins to the common facial vein or passing laterally to the facial vein.
• The sublingual gland drains primarily to submental nodes.
• via the submandibular ganglion,
• Nerves passing to the sublingual gland leave the ganglion and region the lingual nerve, before departing again to supply their target organ
• Sub lingual , Y-Mylohyoid, T – Hyoglossus
• Local invasion is the initial route of spread of malignant tumors of the salivary glands, depending on location and histologic type. For parotid tumors, this may result in fixation to structures in around 20% of cases . Skin invasion is more often seen in parotid tumors (10%), compared with submandibular tumors (3%) .
• Approximately 25% of patients with a malignant parotid salivary gland tumor present with facial palsy from cranial nerve invasion
• Three of four parotid masses are benign .
• Patients most often have a painless, rapidly enlarging mass, often present for years before a sudden change in its indolent growth pattern prompts the patient to seek medical attention
Duration of clinical symptoms before diagnosis may last more than 10 years . For malignant tumors, the median duration of clinical symptoms generally is shorter (3 to 6 months) compared to that of benign tumors, although for some minor salivary gland tumors, median periods of 2 year have been reported .
• Pain is more frequently associated with malignant disease.
• Although as many as one third of parotid cancers may have facial nerve involvement, only 10% to 20% of patients complain of pain .
• Pain may appear with involvement of deeper structures (masseter, temporal, and pterygoid muscles).
Rarely, tumors of the parotid may involve the base of skull and cause intractable pain and paralysis of various cranial nerves.
NASOPHARYNX PARANASAL SINUSES AND SALIVARY GLANDS PPT
NASOPHARYNX PARANASAL SINUSES AND SALIVARY GLANDS PPTX
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