Parotid Gland

TA: DaniOctober 3rd, 2009

Parotid Gland

• Largest salivary gland• Lies below external auditory meatus wedged

between ramus of mandible and SCM• Enclosed within parotid fascia

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

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

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

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

Blood Supply

• Arteries– External carotid– Maxillary– Superficial temporal – Transverse facial

• Veins– Primarily retromandibular and its tributaries

Lymphatic Drainage

• Drain into parotid nodes (superficial and deep) which, in turn, drain directly or indirectly into superficial and deep cervical nodes

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

Relationships of Parotid Gland

• Posteriorly– Occipital vein– Posterior auricular artery

• Inferiorly– Cervical branch of CNVII

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)

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)

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