Parotid gland is the largest of the salivary glands.

Located in a compartment anterior to the ear and is invested by fascia that suspends the gland from the zygomatic arch.

The parotid compartment contains the parotid gland, nerves, blood vessels, and lymphatic vessels, along with the gland itself.

The compartment is divided into superficial, middle, and deep portions but has no discrete anatomic divisions.

Parotid masses associated with facial paralysis are nearly universally malignant.

Facial nerve involvement portends a poor prognosis.

Superficial portion of the parotid gland contains the facial nerve, great auricular nerve, and auriculotemporal nerve.

The middle portion of the parotid contains the superficial temporal vein, which unites with the internal maxillary vein to form the posterior facial vein.

The deep portion contains the external carotid artery, the internal maxillary artery, and the superficial temporal artery.

The parotid compartment is bounded superiorly by the zygomatic arch, anteriorly by the masseter muscle, lateral pterygoid muscle, and mandibular ramus, and inferiorly by the sternocleidomastoid muscle and the posterior belly of the digastric muscle.

The deep portion lies lateral to the parapharyngeal space, styloid process, stylomandibular ligament, and carotid sheath.

The parotid is a unilobular gland and no true superficial and deep lobes exist.

Superficial parotidectomy refers to the surgically created boundary from facial nerve dissection.

The parotid gland is drained by the Stensen duct, and opens intraorally near the second molar.

After entering the parotid gland the facial nerves divides into 2 major divisions: the upper and lower divisions.

The external carotid artery provide arterial supply to the parotid gland.

The posterior facial vein provides venous drainage, and lymphatic drainage is from lymph nodes within and outside of the gland that leads to the deep jugular lymphatic chain.

Acute suppurative parotiditis usually caused by Staphylococcus aureus infection in severely dehydrated patients with decreased salivary flow.

14% cases of parotid malignancy are associated with facial nerve paralysis and involvement is associated with a 5-year survival rate of 9%.

Acute suppurative parotiditis typically occurs in newborns, immunocompromised patients and those recovering from abdominal surgery and who have inadequate fluid replacement.

Enlargement associated with acute and chronic viral infections, granulomatous diseases, malnutrition, alcoholism and diabetes mellitus.

Parotid gland enlargement can be seen in association with HIV infection with infiltration with lymphocytosis syndrome, amyloidosis,  non-Hodgkin’s lymphoma, Hodgkin’s disease, Kaposi’s sarcoma, HIV, hepatitis C, alcoholism and squamous cell carcinoma.

Bilateral enlargement occurs in 30% of patients with sarcoidosis.

Bilateral parotid gland swelling  is common in Sjogren syndrome.

Differential diagnoses to consider in patients with parotid enlargement include:

Viral infection (eg, mumps, Epstein-Barr virus, cytomegalovirus, coxsackievirus A, influenza)

 HIV disease

Granulomatous diseases (sarcoidosis, tuberculosis, leprosy)


Hepatic cirrhosis

Hepatitis C


Recurrent parotiditis of childhood

Chronic pancreatitis



Gonadal hypofunction

Diabetes mellitus

Salivary gland tumor 

Bacterial infection

Chronic sialadenitis



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