Accessory parotid gland
Accessory parotid glands are a normal variant and represent ectopic salivary tissue separate from, but usually in close proximity to, the main parotid glands.
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Epidemiology
Accessory parotid glands are commonly picked up incidentally on ultrasound; seen in ~20% of the general population 2.
Gross anatomy
Located on the lateral aspect of the masseter muscle, anterior to the main parotid gland, usually superior (occasionally anterior) to the main parotid duct (Stensen duct) 2,3. They are, on average, within 6 mm of the main parotid gland 8.
Accessory parotid glands have their own blood supply and secondary duct emptying into the main parotid duct 4.
Radiographic features
Accessory parotid glands have the same US echotexture, CT density and MRI signal as the main parotid glands.
Differential diagnosis
- facial process of the parotid gland 8
Related pathology
Any disorder that affects the main parotid gland may also affect the accessory parotid tissue, but tumors of the accessory parotid glands are rare 5,6.
Related Radiopaedia articles
Anatomy: Head and neck
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cranial vault
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sutures
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cranial vault
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- levator labii superioris muscle
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- malaris muscle
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- depressor labii inferioris muscle
- depressor anguli oris muscle
- mentalis muscle
- compound sphincter
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arterial supply
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trigeminal nerve (CN V) (mnemonic)
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- facial nerve (CN VII)
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vestibulocochlear nerve (CN VIII)
- vestibular ganglion (Scarpa's ganglion)
- glossopharyngeal nerve (CN IX)
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vagus nerve (CN X)
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ansa cervicalis
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cranial nerves
- lymphatic drainage of the head and neck
- embryological development of the head and neck