The parotid gland is the largest of your three major salivary glands, sitting just below and in front of each ear. You have two of them, one on each side of your face, and together they produce roughly half of all the saliva in your mouth. Each gland measures about 5.8 centimeters long and 3.4 centimeters wide, weighing around 14 grams.
Where the Parotid Gland Sits
The gland’s inner surface rests against your jawbone and the masseter muscle, the thick muscle that connects your lower jaw to your cheekbone. You can feel this muscle tighten when you clench your teeth. The gland wraps around the back edge of the jaw, which is why swelling in this area creates that distinctive chipmunk-cheek appearance.
Saliva leaves the gland through a single tube called the parotid duct, which runs about 11 centimeters across your cheek. It travels roughly 1.5 centimeters below the cheekbone, crosses over the masseter, then pierces through the cheek muscle and opens into your mouth right next to your upper second molar. You can sometimes spot the tiny opening if you look in a mirror and pull your cheek to the side.
What the Parotid Gland Does
The parotid gland produces a thin, watery saliva rich in amylase, an enzyme that begins breaking down starches the moment food enters your mouth. This is why bread or crackers start to taste slightly sweet if you chew them long enough. The gland ramps up production when you eat, smell food, or even think about food for an extended time. Between meals, it contributes a steady background flow that keeps your mouth moist and helps protect your teeth from decay.
The Facial Nerve Connection
One of the most important things about the parotid gland is what runs through it. The facial nerve, which controls the muscles of facial expression on each side, branches out through an opening near the gland and fans across the face. This intimate relationship matters because any surgery on the parotid gland carries a risk of affecting the nerve, and any tumor growing inside the gland can press against it.
A separate set of nerve fibers controls saliva production itself. Parasympathetic fibers from the facial nerve signal the gland to release saliva in response to taste and chewing. This wiring becomes relevant in certain complications discussed below.
Parotid Gland Swelling (Parotitis)
Inflammation of the parotid gland, called parotitis, has several causes. The most well-known is mumps, a viral infection that typically causes severe swelling on both sides of the face. Mumps is far less common today thanks to the MMR vaccine, but it still occurs. Many other viruses can also trigger parotid swelling.
Bacterial infections, particularly staph infections, represent another cause. These tend to develop when saliva flow drops, such as during dehydration or after surgery, allowing bacteria to travel up the duct into the gland. Bacterial parotitis more often affects one side and can produce pus from the duct opening inside the mouth.
Common symptoms of acute parotitis include:
- Pain and tenderness where the gland is swollen
- Fever and chills
- Headache and sore throat
- Fatigue and loss of appetite
Chronic, recurring parotitis is a different pattern. It causes repeated episodes of mild swelling, often without much pain. When dry mouth and dry eyes accompany chronic parotid swelling, an autoimmune condition called Sjögren’s syndrome may be the underlying cause.
Salivary Stones
Mineral deposits can form inside the parotid duct, partially or completely blocking saliva flow. A stone the size of a pea can cause sudden, intense pain when you eat, because the gland produces a surge of saliva that has nowhere to go. The pain and swelling typically last one to two hours after a meal, then fade until you eat again. This predictable meal-related pattern is the hallmark symptom and a strong clue for diagnosis.
Parotid Tumors
The parotid gland is the most common site for salivary gland tumors, though the majority are benign. The most frequent benign tumor is a pleomorphic adenoma, a slow-growing, painless lump that can sit in the gland for years before someone notices it. The most common malignant tumor is mucoepidermoid carcinoma.
A painless lump near the ear or along the jawline is the typical presentation. Benign tumors generally feel smooth and mobile under the skin. Warning signs that raise concern for malignancy include rapid growth, pain, and facial weakness on the affected side, since a cancerous growth is more likely to invade the facial nerve.
How Parotid Problems Are Diagnosed
Ultrasound is the first imaging step for any parotid swelling or lump. It’s quick, painless, widely available, and good at distinguishing solid masses from fluid-filled cysts. If a nodule is found, a fine-needle aspiration biopsy typically follows. This involves inserting a thin needle into the lump to collect cells for examination under a microscope. MRI or CT scans are sometimes added for deeper evaluation, particularly when a tumor appears to extend into surrounding tissue.
Surgery and Its Risks
Removing part or all of the parotid gland (parotidectomy) is the standard treatment for most parotid tumors. Because the facial nerve threads through the gland, the surgeon must carefully identify and preserve it during the procedure. In a large analysis of parotid surgeries, facial nerve weakness occurred in about 20% of patients. The reassuring detail: most of that weakness was temporary, resolving on its own. Permanent facial nerve damage occurred in roughly 4.5% of cases.
Another notable post-surgical complication is Frey’s syndrome, a condition where eating triggers sweating on the cheek, temple, or around the ear instead of triggering saliva production. This happens because damaged parasympathetic nerve fibers, the ones that originally told the gland to make saliva, regrow along the wrong pathways and connect to sweat glands in the skin. The result is a peculiar “rewiring” where the signal to salivate instead produces sweating and flushing. Frey’s syndrome is not dangerous, but it can be socially uncomfortable.