Parotid Gland


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Parotid Gland

  1. 1. Parotid Gland TA: Dani October 3rd, 2009
  2. 2. Parotid Gland • Largest salivary gland • Lies below external auditory meatus wedged between ramus of mandible and SCM • Enclosed within parotid fascia
  3. 3. Parotid Gland • Portion of parotid fascia forms the stylomandibular ligament which separates the parotid and submandibular glands; preventing pus from being readily spread between the two • Consists of superficial and deep parts with facial nerve lying between
  4. 4. Parotid Gland • Structures traversing parotid: – Facial nerve – Retromandibular vein – Auriculotemporal nerve – Lymph nodes – External carotid artery which divides within parotid gland into its terminal branches • Superficial temporal • Maxillary
  5. 5. Parotid Gland • Parotid duct (Stenson’s duct) crosses masseter below the zygomatic arch and pierces buccinator to open in the mouth opposite upper second molar tooth
  6. 6. Innervation • Auriculotemporal nerve – Conveys sensory, parasympathetic (secretory) and sympathetic (vasoconstriction) fibers to parotid gland – Parasympathetic fibers reach gland by circuitous route • Preganglionic parasympathetic secretomotor fibers originating from the inferior salivatory nucleus (medulla) pass through the glossopharyngeal nerve, tympanic nerve, tympanic plexus and lesser petrosal nerve to synapse in the otic ganglion • Postganglionic fibers then pass to the parotid gland by way of the auriculotemporal nerve
  7. 7. Blood Supply • Arteries – External carotid – Maxillary – Superficial temporal – Transverse facial • Veins – Primarily retromandibular and its tributaries
  8. 8. Lymphatic Drainage • Drain into parotid nodes (superficial and deep) which, in turn, drain directly or indirectly into superficial and deep cervical nodes
  9. 9. Relationships of Parotid Gland • Superiorly – Superficial temporal artery and vein – Auriculotemporal nerve – Temporal and zygomatic branches of CNVII • Anteriorly – Tranverse facial artery – Parotid duct – Buccal and mandibular branches of CNVII
  10. 10. Relationships of Parotid Gland • Posteriorly – Occipital vein – Posterior auricular artery • Inferiorly – Cervical branch of CNVII
  11. 11. Clinical Notes • Malignant tumor of parotid can involve the facial nerve and produce facial palsy • The chief hazard in surgery of the parotid gland is the facial nerve • Pain sensation in the parotid gland (from mumps for example) is carried by the mandibular nerve (auriculotemporal branch)
  12. 12. Clinical Notes • Facial Nerve Palsy – Paralysis of muscles of facial expression and affects taste (chorda tympani), lacrimation (greater superficial petrosal nerve) and hearing (nerve to stapedius) – Paralysis of stapedius results in hyperacusis (increased perception of loudness) – Paralysis of muscles of facial expression is manifested in some of the following ways • Collection of food between cheek and teeth (buccinator) • Inability to shut the eye (orbicularis oculi) • Inability to wrinkle the forehead (occipitofrontalis and corrugator supercilii) • Sagging of corner of mouth (levator angular oris and zygomatic muscles)
  13. 13. Clinical Notes • Trigeminal Neuralgia – Characterized by severe facial pain along the areas innervated primarily by the mandibular and maxillary divisions of the trigeminal nerve – Relieved by injecting alcohol or novocaine into the trigeminal ganglion