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Parotid gland

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Parotid gland

  1. 1. SEMINAR PAROTID GLAND Presented By:- Dr. Amrita Rastogi M.D.S 1st Year
  4. 4. INTRODUCTION [1] [2] [3]  The salivary glands in mammals are a group of compound exocrine glands, glands with ducts, that produce saliva.  They are: • Parotid gland • Sub mandibular gland • Sublingual gland • Minor salivary glands
  5. 5.  Parotid region contains the largest serous salivary gland and the “queen of the face”, the facial nerve.  Parotid gland(Para=around; otic=ear) is the largest major salivary gland.  Parotid gland contains vertically disposed blood vessels and horizontally situated facial nerve and various branches.
  6. 6.  Paired parotid glands lying largely below the external acoustic meatus between mandible and sternocleidomastoid muscle and it also projects forwards on the surface of masseter. Sternomastoid External acoustic meatus Ramus of mandible
  7. 7.  Occupies the deep hollow behind the ramus of the mandible.  Wedge-shaped when viewed externally , with the base above & the apex behind the angle of the mandible.
  8. 8.  On the surface of the masseter, small detached part lies between zygomatic arch and parotid duct called as Accessory parotid gland or ‘socia parotidis’
  9. 9. • It is irregular, wedge shaped, and unilobular. Parotid is 14-28 grams in weight and provides 60- 65% of total salivary volume. • Dimensions:- averaging 5.8 cm ( craniocaudal dimension), 3.4 cm (ventraldorsal dimension).
  10. 10. Parotid Capsule [1][3]  The investing layer of the deep cervical fascia forms a capsule for the gland. The fasica splits(between the angle of the mandible and the mastoid process) to enclose the gland.
  11. 11.  Consists of :- 1) Superficial layer – It is thick and adherent to gland. It extends from the masseter and Sternocliedomastoid to the Zygoma, 2) Deep layer – It is thin and is attached to the styloid process, the mandible and the tympanic plate.
  12. 12.  A portion of the deep lamina extending between the styloid process and the mandible, is thickened to form the stylomandibular ligament which separates the parotid glands from submandibular salivary gland.  The attachments of the Parotid fascia include :  Anterior – Mandible  Inferior – Stylomandibular ligament  Posterior –Styloid process
  13. 13. Surface Marking [5]  The parotid gland is marked by joining the following four points with each other. a b c d
  14. 14. a) The first point at the upper border of the head of the mandible. b) The second point just above the center of the masseter muscles. c) The third point posteroinferior to angle of mandible. d) The fourth point is anterior border of the mastoid process.
  15. 15. External Features. [1] [2] [5]  The gland resembles a three sided pyramid. The apex of the pyramid is directed downwards.  The gland has four surfaces:- 1) Superior (base of the pyramid) 2) Superficial 3) Anteromedial and 4) Posteromedial The surfaces are separted by 3 borders: a) Anterior b) Posterior and 3) Medial
  16. 16. Apex Superior surface (Base) Superficial surface Posterior border Medial border Anterior border
  17. 17. Development [5] [6] [7]  The parotid salivary glands appear early in the fourth week of prenatal development and are the first major salivary glands formed as an ectodermal furrow.  The epithelial buds of these glands are located on the inner part of the cheek, near the labial commissures of the primitive mouth.  These buds grow posteriorly toward the otic placodes of the ears and branch to form solid cords with rounded terminal ends near the developing facial nerve.
  18. 18.  Later, at around 10 weeks of prenatal development, these cords are canalized and form ducts, with the largest becoming the parotid duct for the parotid gland.
  19. 19.  The rounded terminal ends of the cords form the acini of the glands. Secretion by the parotid glands via the parotid duct begins at about 18 weeks of gestation. Again, the supporting connective tissue of the gland develops from the surrounding mesenchyme.
  20. 20. Relations [1] [2] [3]  The apex: It overlaps the posterior belly of the diagastric and the adjoining part of the carotid triangle. The cervical branch of the facial nerve and the two divisions of the retromandibular vein emerge through it.
  21. 21.  The superior surface or base forms the upper end of the gland : It is small and concave. It is related to: (a) The cartilagious part of the external acoustic meatus. (b) the posterior surface of the temporo mandibular joint (c) the superficial temporal vessels. (d) the auriculotemporal nerve.
  22. 22.  The superficial surface: It is the largest of the four surfaces. It is covered with: (a) Skin (b) Superficial fascia containing the anterior branches of great auricular nerve, the perauricular or superficial parotid lymph nodes and the posterior fibers of the platysma and risorius. (c) the parotid fascia which is thick and adherent to gland .
  23. 23. (d) a few deep parotid lymph nodes embedded in the gland.
  24. 24.  The anteromedial surface: It is grooved by posterior border of the ramus of the mandible. It is related to: (a) The Masseter (b) The lateral surface of temporomandibular joint. (c) The posterior border of the ramus of the mandible. (d) The medial pterygoid. (e) The emerging branches of the facial nerve.
  25. 25.  The posteromedial surface: It is moulded to the mastoid and styloid processes and the structures attached to them. They are related to: (a)The mastoid process, with the sternocleidomastoid and posterior belly of diagastric. (b) The styloid process The external carotid artery enters the gland through this surface and internal carotid artery lies deep in the styloid process.
  26. 26.  Anterior border  Separates superficial surface from anteromedial surface.  Structures which emerge at this border  Parotid Duct  Terminal Branches of facial nerve  Transverse facial vessels
  27. 27.  Posterior Border  Separates superficial surface from posteromedial surface  Overlaps sternocleiodomastoid.  Medial Border  Separates anteromedial surface from posteromedial surface  Related to lateral wall of pharynx
  28. 28. Structures within the Parotid Gland [2] [3]  Arteries • The external carotid artery • The maxillary artery • Superficial temporal vessels • The posterior auricular artery Superficial temporal Artery Maxillary Artery Posterior auricular artery External carotid
  29. 29.  Veins The retromandibular veins is formed within the gland by the union of the superficial temporal and maxillary veins. In the lower part of the gland, the vein divides into anterior and posterior divisions which emerge at the apex of the gland. Superficial temporal Vein Maxillary Vein Post auricular Vein External jugular vein Common Facial Vein Retromandibular vein Posterior divisionAnterior division
  30. 30.  The facial nerve It enters the gland through the upper part of its posteriomedial surface, and divides into its terminal beanches within the glands. Branches appear on the surface at the anterior border. Facial nerve Temporal Branch Zygomatic Branches Upper buccal branch Lower buccal branch Marginal mandibular branch Cervical Branch
  31. 31. Processes [7] The gland is an irregular lobulated mass, sends ‘processes’ in various directions. These include:  Glenoid process- that extends upward behind the temporo-mandibular joint, in front of external auditory meatus
  32. 32.  Facial process- that extends anteriorly onto the masseter muscle  Accessory process (part)- small part of facial process lying along the parotid duct
  33. 33.  Pterygoid process-that extends forward from the deeper part, lies between the medial pterygoid muscle & the ramus of mandible  Carotid process-that lies posterior to the external carotid artery
  34. 34. Parotid Duct [5] [6] [8]  ductus parotideus; Stensen’s duct  It is thick walled and about 5cm long and 5 mm in diameter  Carries saliva to the oral cavity.  Course :- Forms by the union of smaller duct from the gland and run forwards and slightly downward on the masseter.
  35. 35.  Relations Superiorly: (a) Accessory parotid gland. (b) upper buccal branch of the facial nerve. (c) the transverse facial vessels. Inferiorly: (a) The lower buccal branch of the facial nerve.
  36. 36.  At the anterior border of the masseter, it turns medially and pierces: (a) the buccal pad of fat. (b) the buccalpharyngeal fascia (c) the buccinator “Because of the oblique course of the duct through the buccinator infaltion of the duct is prevented during blowing.”
  37. 37.  The duct runs forward for a short distance between the buccinator and the oral mucosa.  The duct turns medially and opens into the vestibule of the mouth (gingivo- buccal vestibule) opposite the crown of the upper molar tooth.
  38. 38. Nerve Supply [1] [5] [9] PARASYMPATHETIC(SECRETOMOTOR) SUPPLY-derived from auriculo temporal nerve Its stimulation produces watery secretion. They reaches the gland through the auriculotemporal nerve.
  39. 39.  Pathway Inferior salivatory nucleus Preganglionic fibres Glossophargeal nerve (ix cranial nerve) tympanic branch tympanic plexus from lesser petrosal nerve- otic ganglion postga nglion ic fibres auriculo emporal nerve The parotid gland To supply
  40. 40. SYMPTHETIC SUPPLY- they are vasomotor, and are derived from the plexus around the external carotid artery. Stimulation produces thick sticky secretion.  SENSORY NERVES-comes from the auriculotemporal nerve, but the parotid fascia is innervated by the sensory fiberes of the great auricular nerve.
  41. 41. Lympatic Drainage [9] [10]  Lymph drains first to the parotid nodes and from there to the upper deep cervical nodes.
  42. 42. Parotid lymph nodes The parotid lymph nodes lie partly in the superficial fascia and partly deep to the deep fascia over the parotid gland.  They drain:- (a) the temple (b) the side of the scalp (c) the lateral surface of the auricle (d) the external acoustic meatus (e) the middle ear (f) the parotid gland
  43. 43. (g) the upper part of cheek (h) parts of the eyelids (i) orbit  Efferents from these nodes pass to the upper groups of the deep cervical nodes.
  44. 44. Histology [4] [7]  The salivary glands are a group of compound exocrine glands secreting saliva. Salivary glands are composed of serous and mucous acini, the proportions of which determine the type of salivary secretion from each duct.
  45. 45. The Secretory Unit – Acinus (serous, mucous, mixed) – Myoepithelial cells – Intercalated duct – Striated duct – Excretory duct
  46. 46.  The parotid gland is a pure serous gland.  All acinar cells are similar in structure to the serous cells. In the infants, however, a mucous secretory units may be found.  The intercalated ducts of the parotid gland are long and branching and numerous in striated ducts.  The connective tissue septa in the parotid contain numerous fat cells, which increases in number with age and leave an empty space in histological sections.
  47. 47. Functions of parotid glands [9] [10] [11]  Protection of the oral cavity and oral enviroment: the constant secretion of saliva prevents desiccation of oral cavity.  Lubrication and cleansing oral cavity: provides a washing action to flush away debris and nonadherent bacteria and provide lubrication for smooth and sliding movement.
  48. 48.  Initiation of starch digestion: the action of amylase on ingested carbohydrate to produce glucose and maltose in the mouth.  Immunological: defensive substance in saliva are the immunoglobulins. The perdominant salivary immunoglobulin is IgA.  Parotid gland is the largest, provides 65% of the total salivary volume. Normal outflow is 1-2L/day.
  49. 49. Clinical considerations [9]  Diseases of parotid gland 1) Congenital Aplasia or atresia- any one or group of salivary glands may be absent, unilaterally or bilaterally. Aplasia occurs for unkown reasons in conjunction with other development defects such as hemifacial microsomia, the LADD syndrome and mandibulo- facial dysostosis.
  50. 50.  Salivary loss leads to increased caries, burning sensation, oral infections, taste aberrations and difficulty with denture retention.
  51. 51. 2) Acquired Infective Mumps Bacterial sialadentitis Autoimmune Sjögren's syndrome Inflammatory Sialadenitis Neurological Frey's syndrome
  52. 52. Neoplastic Salivary gland neoplasm Idiopathic Sialolithiasis Sialadenosis
  53. 53.  Mumps [10]  Its a viral disease of the human species, caused by the mumps virus Paramyxovirus. Transmitted by direct contact, droplet spread, or contaminated objects. Painful swelling of the parotid gland.
  54. 54. Fever and headache are the main symptoms of mumps, together with malaise and anorexia. Other symptoms of mumps can include dry mouth, sore face and/or ears and occasionally in more serious cases, loss of voice.
  55. 55.  It was a common childhood diseases worldwide. The disease is generally self-limiting, running its course before receding, with no specific treatment apart from controlling the symptoms with pain medication.
  56. 56.  Bacterial parotitis [11] [16]  It can be acute, chronic and recurrent. The most common pathogens associated with acute bacterial parotitis are Staphylococcus aureus and anaerobic bacteria. The predominant anaerobes include gram-negative bacilli. It often occurs in the setting of debilitation, dehydration, and poor oral hygiene, particularly among elderly postoperative patient
  57. 57.  Once an abscess has formed surgical drainage is required. The choice of antimicrobial depends on the etiologic agent. Maintenance of good oral hygiene, adequate hydration, and early and proper therapy of bacterial infection of the oropharynx may reduce the occurrence of suppurative parotitis.
  58. 58.  Sjögren's syndrome [7] [8] Chronic inflammation of the salivary glands may also be an autoimmune disease known as Sjögren's syndrome  The disease most commonly appears in people aged 40–60 years, but it may affect small children.
  59. 59. Women versus men is approximately 9:1. The involved parotid gland is enlarged and tender at times. The cause is unknown. The syndrome is often characterized by excessive dryness in the eyes, mouth, nose, vagina, and skin
  60. 60.  Frey’s Syndrome [12] [13] Also known as gustatory sweating or auriculo- temporal nerve syndrome. Commonly occurs after parotid surgery or trauma. It reflects the aberrant innervation of sweat glands on the face by regrowing parasympathetic secretomotor axons that would have previously innervated the parotid gland.
  61. 61. It is characterized by o Sweating o Warmth o Redness of the face as a result of salivary stimulation by the smell or taste of food
  62. 62.  There is no effective treatment, but various options are:- Injection of Botulinum Toxin A. Surgical transection of the nerve fibers (only a temporary treatment). Application of an ointment containing an anticholinergic drug such as scopolamine.
  63. 63.  Sialadenitis (sialoadenitis) [11] [12]  It is the inflammation of a salivary gland. It may be subdivided into acute, chronic and recurrent forms. Acute • sialolithiasis • decreased flow (dehydration, post-operative, drugs) • poor oral hygiene • exacerbation of low grade chronic sialoadenitis
  64. 64. Clinical features • Painful swelling • Reddened skin • Edema of the cheek, Periorbital region and neck • low grade fever • malaise • raised ESR, CRP, leucocytosis • purulent exudate from duct punctum
  65. 65. Chronic • Clinical Features unilateral • mild pain / swelling • common after meals • duct orifice is reddened and flow decreases • may or may not have visible/palpable stone. • Recurrent painful swellings
  66. 66. Treatment • In chronic recurrent sialadenitis or chronic sclerosing sialadenitis, acute attacks are managed with conservative therapies such as hydration, analgesics (mainly NSAIDs), sialogogues to stimulate salivary secretion, and regular, gentle gland massage.
  67. 67. • If infection is present, appropriate cultures should be obtained, followed by empirical antibiotic therapy initially, for example amoxicillin/clavulanate or clindamycin which cover oral flora. If there are attacks more than approximately 3 times per year or severe attacks, surgical excision of the affected gland should be considered.
  68. 68.  Salivary gland neoplasm [7] [10] [12] [13] Salivary gland cancer is a cancer that forms in tissues of a salivary gland. Salivary gland cancer is rare, with 2% of head and neck tumors forming in the salivary glands, the majority in the parotid. Salivary gland neoplasms are classified by the World Health Organization as primary or secondary, benign or malignant, and by tissue of origin. This system defines five broad categories of salivary gland neoplasms.
  69. 69.  Malignant epithelial tumors (e.g. acinic cell carcinoma, mucoepidermoid carcinoma and adenoid cystic carcinoma, salivary duct carcinoma)  Benign epithelial tumors (e.g. pleomorphic adenoma, myoepithelioma and Warthin tumour, sebaceous lymphadenoma)  Soft tissue tumors (Hemangioma)  Hematolymphoid tumors (e.g. Hodgkin lymphoma)  Secondary tumors.
  71. 71.  Signs and symptoms Signs include fluid draining from the ear, pain, numbness, weakness, trouble swallowing, and a lump. The most common symptom of major salivary gland cancer is a painless lump in the affected gland, sometimes accompanied by paralysis of the facial nerve.
  72. 72.  Causes The chief risk factor is chewing tobacco, followed by smoking. Other risk factors include older age, radiation therapy treatment to head or neck, and being exposed to certain carcinogenic substances at work. Treatment • Surgery with or without radiation. • Radiation therapy. • Chemotherapy.
  73. 73.  Sialolithiasis [11] [12] Sialolithiasis (also termed salivary calculi, or salivary stones), is a condition where a calcified mass forms within a salivary gland, usually in the duct of the submandibular gland (also termed "Wharton's duct"). Less commonly the parotid gland.
  74. 74.  Signs and symptoms Signs and symptoms are variable and depend largely upon whether the obstruction of the duct is complete or partial, and resultant pressure created within the gland. The development of infection in the gland also influences the signs and symptoms.
  75. 75. Pain, which is intermittent, and may suddenly get worse before mealtimes, and then slowly get better (partial obstruction). Swelling of the gland, also usually intermittent, often suddenly appearing or increasing before mealtimes, and then slowly going down (partial obstruction).
  76. 76. Tenderness of the involved gland. Palpable hard lump, if the stone is located near the end of the duct. If the stone is near the submandibular duct orifice, the lump may be felt under the tongue. Lack of saliva coming from the duct (total obstruction). Erythema (redness) of the floor of the mouth (infection). Pus discharging from the duct (infection). Cervical lymphadenitis (infection).
  77. 77.  Treatment  Non-invasive: For small stones, hydration, moist heat therapy, NSAIDs (nonsteroidal anti-inflammatory drugs)  Some stones may be massaged out by a specialist.  Shock wave therapy (Extracorporeal shock wave lithotripsy).  Minimally invasive: Sialendoscopy
  78. 78. Surgical Supporting treatment: To prevent infection while the stone is lodged in the duct, antibiotics are sometimes used.
  79. 79. Role of public health dentist [15]  During the treatment of oral cancer affecting salivary glands leading to surgical removal of the glands, leads to decreased or no saliva secretion. This increases the incidence of dental caries.  Patient under the high dose of radiation therapy reduce the quality and quantity of normal saliva, causing radiation caries.
  80. 80.  Fluoride application  Maintaining the periodontal health.  Educating about proper nutrition and good oral hygiene.  Dentures reconstruction in case of altered oral tissue.  Educating and motivating people about tobacco cessation.
  81. 81. Conclusion  The parotid glands are a pair of mainly serous salivary glands located inferior and anterior to the external acoustic meatus, draining their secretions into the vestibule of oral cavity through the Stensen duct or parotid duct.  The parotid gland also secretes salivary alpha-amylase (sAA), which is the first step in the decomposition of starches during mastication.
  82. 82.  Parotid gland is the largest, it provides 65% of the total salivary volume. The serous cell predominates in the parotid, making the gland secrete a mainly serous secretory product.  Apart from viral infection, other infections, such as bacterial, can cause parotitis (acute suppurative parotitis or chronic parotiti). These infections may cause blockage of the duct by salivary duct calculi or external compression.
  83. 83.  About 80% of tumors of the parotid gland are benign. Surgical treatment of parotid gland tumors is sometimes difficult because of the anatomical relations of the facial nerve parotid lodge, as well as the increased potential for postoperative relapse. Thus, detection of early stages of a parotid tumor is extremely important.
  84. 84. References 1) Guyton and Hall ;Textbook of medical physiology 9th edition pg no. 223-254. 2) Tortora-Derrickson; Principal of anatomy and physiology,12th edition pg no. 112-114. 3) Chaudhuri; Concise medical physiology , 2nd edition. Pg no. 34-36. 4) A.K.Jain Human physiology ,1st edition. Pg no. 454- 456.
  85. 85. 5) K.Sembulingum,P.Sembulingum;Essentials of medical physiology,4th edition pg no.555-557. 6) Burket’s ;Oral medicine ,11th edition pg. no. 211-213. 7) Principal of anatomy and physiology- tortora- derrickson ,12th edition. 8) Richard Tencate ;ORAL HISTOLOGY-5th edition pg. no. 339-342. 9) Robert M Bradley ;ESSENTIALS OF ORAL PHYSIOLOGY pg. no. 221-223 10) G.Neil Jenkins ;The physiology and biochemistry of the mouth, 4th edition 11-13
  86. 86. 11) Christopher L B Lavelle ;APPLIED ORAL PHYSIOLOGY-2nd edition. 12) Greenberg& Glick ;BURKETS ORAL MEDICINE- 10th edition pg. no. 41-43 13) Shafer,Hine & Levy ;Textbook of Oral Pathology 6th edition pg. no. 134-144. 14) Saliva:its secretion,composition&functions.- British Dental Journal 1992; 172:305
  87. 87. 15) The effect of saliva on dental caries George K. Stookey, MSD, PhD 10.14219/jada.archive.2008.0347 2008;139(suppl 2):11S-17SJADA 16) J Craniofac Surg. 2003 Jan;14(1):37-40. Acute bacterial suppurative parotitis: microbiology and management.