Salivary Glands PDF

 Anatomy  The submandibular glands are paired salivary glands that they lie in the submandibular space between the digastric muscles and extend upwards deep to the mandible.  They consist of a larger superfcial and a smaller deep lobe that is continuous around the posterior border...

 Anatomy  The submandibular glands are paired salivary glands that they lie in the submandibular space between the digastric muscles and extend upwards deep to the mandible.  They consist of a larger superfcial and a smaller deep lobe that is continuous around the posterior border of the mylohyoid muscle.  The deep part of the gland lies on the hyoglossus muscle in close relation to the lingual nerve.  The gland is drained by a single submandibular duct (Wharton’s duct) that emerges from its deep surface and runs into the anterior floor of the mouth at the sublingual papilla. Important anatomical relationships of the submandibular glands: Lingual nerve Hypoglossal nerve Anterior facial vein Facial artery Marginal mandibular branch of the facial nerve  The most common cause of obstruction within the submandibular gland is stone formation (sialolithiasis) within the gland and its associated duct system.  The submandibular gland is most commonly affected (85%) owing to the ascending course of its duct, predisposing it to stagnation of the mucinous as well as the more viscous saliva it produces.  Eighty per cent of submandibular stones are radio- opaque and can be identified on plain radiography  Patients between the ages of 30 and 60 with sialolithiasis typically present with cyclical postprandial swelling of the major salivary.  The swelling occurs rapidly and often resolves spontaneously over 1–2 hours after the meal is completed (meal-time syndrome).  On examination, there is an asymmetrical enlargement of the gland and a large proximal stone may be palpated in certain cases.  Sialolithiasis complicated by a secondary bacterial infection may present with an abscess.  Conventional radiographs are considered as an initial diagnostic test  computed tomography (CT) scanning ultrasonography and a magnetic resonance sialogram will be more sensitive for diagnosis and localisation.  Sialography is the gold standard for diagnosis and involves injecting a dye into the duct of the salivary gland. It not only helps in diagnosis of sialolithiasis but also identifes any pathology in the duct. In addition, it may be therapeutic in certain cases.  Sialendoscopy provides direct visualisation of the duct and can be used for removal of stones.  The smaller (5 mm) distal stones may require duct slitting.->  Stones that are not palpable and not visualised endoscopically can be removed using external shock wave lithotripsy (ESWL). ‫تفتيت الحصوة‬  gland removal should be considered only as a final remedy.  haematoma;  wound infection;  marginal mandibular nerve injury;  lingual nerve injury;  hypoglossal nerve injury;  transection of the nerve to the mylohyoid muscle producing submental skin anaesthesia.  The parotid gland lies in a recess bounded by the ramus of the mandible, the base of the skull and the mastoid process.  The parotid, unlike other glands in the body, does not become encapsulated early to form a regular gland. The other structures in the vicinity, including the vessels, nerves and lymphatics, develop befor encapsulation.  The gland goes on to envelop the facial nerve, the terminal branches of the external carotid artery, the retromandibular and superfcial temporal vein and the lymph nodes.  The parotid (Stensen’s) duct passes over the masseter muscle and enters the buccal mucosa through the buccinator muscle at the level of the upper second molar tooth.  The facial nerve gets enveloped within the substance of the gland as it grows laterally, dividing the parotid gland into the superfcial and deep lobes.  Most of the lymph nodes lie in the superfcial (preauricular) lobe of the parotid gland lateral to the masseter while very few lie in the deep (retromandibular) lobe of the parotid and so as most of its function(80%).   The parotid gland is the most common site for salivary tumors.  Most tumors arise in the superficial lobe and present as slow- growing, painless swellings below the ear, in front of the ear or in the upper aspect of the neck.  Primary salivary gland neoplasms are extremely rare and form less than 3% of head and neck malignancies.  Warthin’s tumours are more common in older men, while pleomorphic adenomas are slightly more common in women.  Most salivary gland tumours (>80%) occur in the major salivary glands and the majority of them are benign.  The commonest benign neoplasm is the pleomorphic adenoma (mostly seen in the parotid glands), while the commonest malignant tumour is the mucoepidermoid carcinoma followed by adenocystic carcinoma characterised by a high predilection for perineural invasion.  Radiation exposure has been implicated in the development of both benign and malignant salivary gland tumours.  These are the most common benign salivary gland tumours.  They can occur at all ages, but are most commonly seen between the third and sixth decade  They occur most frequently in the parotid glands (>80%  Pleomorphic adenoma presents as a painless, well-defned solitary mobile mass with gradual progression over many years and can reach enormous proportions  When they arise from the deep lobe of the parotid they may present as a paratonsillar bulge.  A sudden increase in size or facial nerve palsy is associated with malignant transformation, which is rare.  Treatment involves surgical excision with a cuf of surrounding normal tissue, where possible, to include the pseudopods from the tumour capsule. Warthing turn in 30-607 Mucoepidermid (0 I Sialouthiasis. - - Pleomorphic Adenoma.  Strong relation with smoking ‫عندو‬  Warthins tumors are the second most common benign salivary gland tumours (5–15%) and are mainly seen in older men, after the sixth decade of life ,associated with cigarette smoking as well as radiation exposure.  They are almost exclusively seen in the parotid gland, especially in the inferior pole.  They can occur synchronously or metachronously in the same or bilateral glands.  They are also known to occur with other salivary gland neoplasms such as pleomorphic adenoma and salivary duct carcinoma.  Malignant transformation is extremely rare (  They generally present as soft to firm, painless masses with a gradual increase in size.  High-grade mucoepidermoid carcinomas tend to be locally aggressive with bone and/or skin involvement and nodal metastases.  Complete surgical excision with wide margins is dvocated for mucoepidermoid carcinoma with or without adjuvent radiotherapy.  The initial imaging modality of choice is ultrasound as it demonstrates if the lump is intrinsic to the parotid or not. It also facilitates accurate sampling of the lesion by FNAC  or True-Cut biopsy.  CT and MRI are the most useful imaging techniques.  haematoma formation;  infection;  deformity: unsightly scar and retromandibular hollowing;  temporary facial nerve weakness;  transection of the facial nerve and permanent facial weakness;  sialocele;  facial numbness;  permanent numbness of the ear lobe associated with great  auricular nerve transection;  Frey’s syndrome.  Frey’s syndrome (gustatory sweating)). It results from damage to the autonomic innervation of the salivary gland with inappropriate regeneration of the postganglionic parasympathetic nerve fibres of the auriculotemporal nerve that aberrantly stimulate the sweat glands of the overlying skin.  The clinical features include sweating and erythema (flushing) over the region of surgical excision of the parotid gland as a consequence ofautonomic stimulation of salivation by the smellor taste of food.  antiperspirants, usually containing aluminium chloride;  denervation by tympanic neurectomy;  the injection of botulinum toxin into the affected skin.  The last is the most effective and can be performed as an out-patient.  References:  SHORT PRACTICE of SURGERY Bailey & Love’s 28th EDITION  BROWSE’S INTRODUCTION TO THE INVESTIGATION AND MANAGEMENT OF  SURGICAL DISEASE  Further readings:  Shwartz manual of surgery.