Salivary Glands PDF

By Dr. Moustafa Roshdy Youssef Mohamed BDS,MOMS(RCSEd), ABOMS Oral and Maxillofacial Surgery Alexandria University STUDY OBJECTIVES  To identify structure, anatomy ,function and diseases of salivary glands  To determine the influence of salivary constituents on oral health  To improve the know...

By Dr. Moustafa Roshdy Youssef Mohamed BDS,MOMS(RCSEd), ABOMS Oral and Maxillofacial Surgery Alexandria University STUDY OBJECTIVES  To identify structure, anatomy ,function and diseases of salivary glands  To determine the influence of salivary constituents on oral health  To improve the knowledge of examination methods of salivary glands and special investigations needed for confirming the diagnosis of any disorder  INTRODUCTION  There are three pairs of major salivary glands consisting of the parotid, submandibular, and sublingual glands  In addition there are numerous minor glands distributed throughout the oral cavity within the mucosa and submucosa.  Minor salivary glands found in the tongue , palatine tonsils ,soft palate ,posterior part of the hard palate , lips and cheeks.  Minor salivary glands are not found in the gingiva or anterior part of hard palate  On average about 0.5 liters of saliva are produced each day but the rate varies throughout the day  At rest, about 0.3 ml/min are produced, but this rises to 2.0 ml/min with stimulation.  Definition : salivary glands are compound , Tubuloacinar , merocrine , exocrine glands the duct of which open into oral cavity  The oral cavity is kept moist by a film of fluid called saliva that coats the teeth and mucosa  Saliva is a complex fluid produced by the salivary glands. NATURE OF SECRETIONS  Sublingual, and many minor salivary glands(MUCOUS)  Parotid, and some minor salivary glands(SEROUS)  Submandibular SEROMUCOUS (MIXED) PROPORTIONS  Parotid 20 %  Submandibular 65 %  Sublingual and minor salivary glands 15 % MORPHOLOGY OF SECRETORY UNITS (MICROSCOPIC ANATOMY )  TUBULAR: Sublingual, and many minor salivary glands  ACINAR: Parotid, and some minor salivary glands  MIXED TUBULOACINAR: Submandibular MYOEPTHILIAL CELLS FUNCTIONS OF SALIVA 1. Lubricates food and assists in deglutition 2. Moistens the oral mucosa to assist speech 3. Protects the oral mucosa from abrasions 4. Provides an aqueous solvent for taste 5. Secretes digestive enzymes, especially amylase 6. Secretes antimicrobial agents, including IgA, lysozyme and lactoferrin 7. Contains calcium and phosphate ions which have a role in the mineralisation of teeth 8. Protects the mouth from ingested acids or alkalis by its buffering capacity  PAROTID GLAND  Size : it is the largest salivary gland. It’s serous in nature.  Site and extension : it lies below the auricle occupying the deep gap between the ramus of the mandible and sternomastoid muscle  Average weight 25gm  EXTENSION 1. Upward : the root of zygomatic arch and external acoustic meatus 2. Downward : at the level of posterior belly of digastric muscle and angle of the mandible 3. Anteriorly : to cover part of masseter muscle. 4. Posteriorly : to overlap sternomastoid muscle. 5. Medially : to the pharyngeal wall. STRUCTURES  Main part : the superfacial part expanded between sternomastoid and masseter muscles  Deep part : medial narrow edge which extended to pharyngeal wall  Accessory part : a small semidetached part lying between the parotid duct and zygomatic arch.  Parotid duct (stensen’s duct ) : 5cm long , it arises from the anterior part of the gland. SURFACE ANATOMY SURFACE ANATOMY OF THE DUCT  It lies opposite the middle third of a line extending from the lower border of the tragus of the ear to a point midway between angle of mouth & ala of the nose SHAPE OF THE GLAND  Wedge shaped : the apex is directed medially towards the pharynx while the base is directed laterally under the skin  SURFACES , BORDERS AND ENDS : (3) SURFACES (3)BORDERS (2) ENDS  3 surfaces : - lateral (superfacial) surface - anteromedial surface - posteromedial surface  Borders : 1-anterior 2- posterior 3- medial  Poles (ends) : 1- upper end 2- lower end RELATIONS OF THE PAROTID GLAND RELATION TO THE UPPER AND LOWER ENDS Upper end : 1. Posteriorly : external audiotry meatus 2. Anteriorly : it gives exit to : a) Temporal branch of facial nerve b) Superfacial temporal vessels c) Auriculotemporal nerve. Lower end :  It lies on posterior belly of digastric m. The following structures appear undercover of it : a) External carotid artery (ascending) b) The two branches of retromandibular vein (descending) c) Cervical branch of facial n. RELATIONS OF ANTERIOR AND POSTERIOR BORDERS Anterior border : it overlaps the masseter muscle and gives exit to the following structures (arranged from above downwards ) : 1. Zygomatic branch of facial nerve 2. Transverse facial artery. 3. Parotid duct. 4. Buccal branch of facial nerve. 5. Marginal mandibular branch of facial nerve. Posterior border : it overlaps the sternomastoid m & is related to : great auricular nerve and mastoid process STRUCTURES INSIDE THE GLAND 1. Facial nerve (most superfacial ) 2. Retromandibular vein ( intermediate in position 3. External carotid ( deepest structure ) 4. Auricular temporal nerve ( embedded in the part of the gland )  Length : 5 cm  Beginning : at the anterior border of the gland CAPSULE OF PAROTID GLAND  Parotid gland has no true fibrous capsule  It acquires a fascial capsule derived from general investing deep fascia of the neck which splits at the lower end of the gland into 2 layers : A- Superficial layer : covering the outer surface of the gland and the masseter muscle and attached above to the zygomatic arch. B- Deep layer : covering the inner surface of the gland & is attached above to the base of the skull. This deep layer forms the stylomandibular ligament which separates the lower pole of parotid from the submandibular salivary gland. BLOOD SUPPLY AND LYMPHATIC DRAINAGE 1. Blood supply : small branches from external carotid artery inside the gland 2. Venous drainage : into the retro-mandibular vein 3. Lymphatic drainage : into deep & superfacial parotid L.N NERVE SUPPLY OF PAROTID GLAND 1. Sensory : a) Auriculo-temporal nerve supplies the parenchyma of the gland b) Great auricular nerve : supplies the capsule and Connective tissue. 2. Parasympathetic : which stimulate saliva secretion (secreto-motor) from glossopharyngeal nerve via auriculo-temporal nerve 3. Sympathetic supply : superior cervical ganglion (sympathetic plexus around external carotid artery ) SUBMANDIBULAR GLAND It lies in the digastric triangle of the neck extending :  Anteriorly : to the mental foramen.  Posteriorly : to the angle of the mandible.  Above : it reaches the mylohyoid line of the mandible  Below : it overlaps the intermediate tendon of the digastric muscle  Size : about half of size of parotid gland  Shape : wedge shaped  Structures : large superfacial & small deep part Both parts are continuous together around the posterior border of the mylohyoid muscle  SURFACES AND RELATIONS OF THE SUPERFACIAL PART 3 surfaces : lateral , medial & inferolateral THE DEEP PART OF SUBMANDIBULAR GLAND  It’s a thin tongue – like process which lies between mylohyoid & hyoglossus muscles.  It’s continuous with the superfacial part at the posterior border of mylohyoid.  It’s related to lingual nerve above & hypoglossal nerve below. THE SUBMANDIBULAR DUCT  It’s 5 cm long & arises from the medial surface of the superfacial part.  It runs through the deep part of the gland then passes forwards between mylohoid & hyoglossus muscles.  Finally it passes between genioglossus (medially) & sublingual gland (laterally).  It ends by opening into the floor of mouth close to the frenulum of tongue. BLOOD SUPPLY AND INNERVATION :  Arterial supply : branches from facial & lingual arteries.  Venous drainage : deep lingual vein  Lymphatic drainage : upper deep cervical L.N  Nerve supply : branches from the submandibular ganglion containing : Sensory : derived from lingual nerve & pass through the ganglion without relay. Sympathetic fibers : derived from the symp. Plexus around facial artery & passing through the ganglion without relay Parasympathetic fibers (secretomotor): facial nerve (chorda tympani ) SUBLINGUAL GLAND Size :This is smallest of the three pairs of large salivary glands weighs about 3–4 g. Site :lies in the floor of the mouth between the mucus membrane and the mylohyoid muscle It is separated from the base of the tongue by the submandibular duct. Shape :It is almond shaped and rests in the sublingual fossa of the mandible. Ducts :The gland pours its secretion by a series of ducts, about 15 in number, into the oral cavity on the sublingual fold, but a few of them open into the submandibular duct. RELATIONS  Superiorly : mucous membrane ( raised to form the sublingual fold )  Inferiorly : mylohoid muscle  Medially : genioglossus muscle separated from the gland by the lingual nerve and submandibular duct.  Anterolaterally : sublingual fossa of the mandible BLOOD SUPPLY AND INNERVATION  Blood supply : 1- Sublingual branch of lingual artery. 2- Submental branch of facial artery.  Venous drainage : Lingual vein.  Lymphatic drainage : Submental lymph nodes.  Innervation : same as submandibular. SALIVARY GLAND DISEASES SALIVARY GLAND DISEASES  Developmental ( very rare )  Obstructive (Sialolethiasis)  Inflammatory (Sialadenitis)  Autoimmune  Tumours  Cysts SIALOLITHIASIS (STONES)  90% of salivary calculi occur in the submandibular gland why ??  Majority of rest occur in the parotid gland  3months  Salivary and lacrimal gland enlargement  Dry skin , nasal, and vaginal mucosa INVESTIGATIONS  Sialography : punctuate sialectasis ( apple bloom tree)  Blood test : ESR , autoantibodies (rheumatoid facto , Anti-Ro , Anti-La ,ANA)  Schirmer test : blotting paper for tear production  The most important : labial gland biopsy  TUMORS  Can be benign or malignant.  Benign tumors: commonest cause of localized salivary swelling  Most common site is parotid:  Commonest benign salivary gland tumor is Pleomorphic Adenoma  2nd most common salivary gland tumor is Warthin’s tumor : Can be bilateral Most commonly with smokers Male predominance MALIGNANT  Adenoid cystic carcinoma  Mucoepidermoid carcinoma  Acinic cell carcinoma  Secondary metastatic deposits from cutaneous SCC of ear and scalp CYSTS 1. Mucous retention cyst : which the mucin pooling is confined within a dilated excretory duct or cyst (mucocele). most commonly in minor salivary gland and the most common site is lower lip 2. Mucous extravasation cyst : in which mucin is spilled into the connective tissues from a ruptured or traumatized salivary gland duct. Most common site is the sublingual gland. MANAGEMENT OF SALIVARY GLAND DISEASES  History  Clinical examination  Investigations  Treatment options HISTORY  Medical history  History of swelling  For how long ?  Does the swelling is increasing in size ?  Is it painful ?  Does the swelling increase and becomes painful with eating ?  Previous radiotherapy ?  Drug history  Pain Swelling Intermittent: related to Incidence eating time (obstructive) No Yes Is it related to Benign or Locatio Persistent malignant n eating time? Tumor UniL. BiL. Generalize No Chronic Infectious Mumps Tumor d: Yes Infection(most inflammator Tumor Ass. Autoimmune infectiou Sjeogren Obstructive ly) y Obstructiv D. s Diabetes Tumor e (Endocrine, AIDS) Alcoholism Warthin’s CLINICAL EXAMINATION Clinical examination of the salivary glands starts with extraoral and intraoral clinical inspection and palpation, including the parapharyngeal space.  PAROTID  Inspection :  Is there parotid swelling ?  Asymmetry (earlobe)  Unilateral or bilateral ?  Any skin changes over the parotid region ? If seen unilaterally may indicate infection or malignancy  Are there any potentially malignant cutaneous lesions on the ear or scalp ?  Facial nerve weakness  sign of malignant tumor  Is there a swelling in oropharynx  deep lobe tumor PALPATION  Always ask the patient first and check whether it’s painful swelling  Is there diffused swelling of parotid gland or localized lamp ?  Is the lump mobile “  Is it possible to produce saliva from the duct ? SUBMANDIBULAR AND SUBLINGUAL  Inspection :  Any obvious swelling below the lower border of the mandible ?  Is there any abnormal tongue movement or senation ?  Is there any weakness of maginal mandibular branch of facial nerve ?  Is there any swelling in the floor of the mouth ?  Is there any pathology that could cause lymphadenopathy of submandibular triangle ? PALPATION  Bi-manually pupate the submandibular gland with one finger in the mouth and a finger over the submandibular triangle. Compare one side to another.  Is there a stone palpable in the submandibular duct ?  Is there any swelling palpable in the submandibular triangle ?  If it’s palpable bi-manually , then it’s suggestive for submandibular gland swelling  If only palpable in the neck , then it’s suggestive for enlarged submandibular lymph node  Submandibular vs sublingual gland swelling  Since the majority of submandibular gland lies in the submandibular triangle most of the swelling will be in the neck and can be palpated bi-manually. In contrast the swelling from sublingual gland will appear exclusively in the mouth INVESTIGATIONS  Plain films  demonstrate calcified salivary stones  Sialography  duct obstruction , sialectasis  USS ( ultrasound sonography )  quick and safe diagnostic procedure with no contraindication. Ultrasonography is the examination of first choice for all lesions of the major salivary glands with abnormal appearance ( tumors , lymph nodes , stoned.. Deep lobe is difficult to visualize  M.R.I  can demonstrate tumors , nodes , stones. Can be combined with ductal contrast to show obstructive disease. High resolution for visualization of facial nerve is debatable  C.T  as M.R.I  FNAC or FNAB  Sialoendoscopy  technique in which an endoscope is passed down the parotid or submandibular duct with a view to diagnosing causes of duct obstruction. It is possible to therapeutically remove calculi or dilate structures using minimally invasive technique CASE 1 What structures that could be injured in this case?  2ND CASE  A 55-year-old female patient complaining of: 1. Inability to eat completely due to loss of teeth. 2. Along with that patient also complained of dryness of mouth, since 1 year, and dryness of eyes since 7-8 years. FINAL DIAGNOSIS Sjogren’s syndrome  3RD CASE  A 55 year-old male patient complaining of intermittent pain and swelling in left submandibular area was admitted. Starting four months ago, the pain was increasing during chewing. The patient’s past medical history was unremarkable RADIOGRAPHIC EXAMINATION AFTER A DICISION OF EXCISING THE GLAND  What vital structures you should tell the patient it could be injured during the surgery in the consent ?  1- marginal mandibular branch of facial nerve  2- lingual nerve  3- hypoglossal nerve  4TH CASE  A 53-year-old female patient complaining about a painless swelling who is a schoolteacher, is referred for evaluation of a mass inferior to her left ear.   The condition started as a small nodule since 5 years Over the past 8 months, the patient had noticed a progressively enlarging mass anterior and inferior to her left ear. There is no associated pain, paresthesias, or motor deficits. She denies any constitutional symptoms, includingfever, chills, night sweats, appetite changes, and weight loss.  Differential diagnosis : 1- pleomorphic adenoma 2- warthin’s tumor 3- myoepthelioma 4- basal cell adenoma FINAL DIAGNOSIS Pleomorphic adenoma REFERENCES  Text book and colour atlas of salivary gland of salivary gland pathology : diagnosis and management(p3-4)  Anatomy of head & neck by dr.sameh doss professor of anatomy faculty of medicine cairo university(p67-p72,p112-p114)  Grey’s anatomy for students 2nd edition by Richard.l.drake , A.wayne vogl , Adam.W.Mitchell(p1515)  Text book of anatomy head , neck and brain volume 3 second edition by vishram singh(p112,p115,p119,p128,p132)  Oxford specialist handbooks in surgery : oral and maxillofacial surgery second edition(p180-p181)  Clinical review of oral and maxillofacial surgery a case based approach 2nd edition (p108-p111)