Anatomy of the salivary glands

Have you ever smelled something so good that your mouth begins to water? Well you can thank your salivary glands for this mouth-watering sensation. The salivary glands, while often overlooked, are a key part of our digestive system.

There are three main pairs of salivary glands: the parotid, submandibular, and sublingual glands. There are also a few smaller companions called accessory salivary glands, which are sprinkled over the palate, lips, cheeks, tonsils, and tongue.

When it comes to function, salivary glands secrete saliva into the oral cavity. Saliva, as you may know, is a clear, tasteless, and odorless fluid that keeps the mouth’s mucosa hydrated.

Saliva also helps lubricate food while we chew, making swallowing easier, and it also starts the digestion of starch, because it contains an enzyme called amylase.

Saliva also acts as ‘nature’s mouthwash’, since it’s rich in antimicrobial compounds such as hydrogen peroxide to keep our mouths clean. Accessory salivary glands have a similar role, except they tend to secrete less saliva.

The parotid glands are the largest of the three paired salivary glands. Superficially, each parotid gland is triangular in shape, where it sits upon the masseter muscle.

However, most of the parotid gland actually sits in the retromandibular fossa, anteroinferior to the external acoustic meatus, where it is wedged between the the ramus of the mandible and the mastoid process and sternocleidomastoid muscle posteriorly.

Its apex is situated posterior to - or along - the angle of the mandible, while the base is associated with the zygomatic arch.

The parotid gland is surrounded by a protective sheath derived from the investing layer of the deep cervical fascia called the parotid sheath.

Now, a number of structures are closely associated with the parotid gland. First the extracranial portion of the facial nerve passes through the parotid gland and forms the parotid plexus.