Parotid duct

Last revised by Jenny Bramley on 16 Jun 2023

The parotid duct, also known as Stensen duct, drains saliva from the parotid gland into the oral cavity.

Following confluence of two main tributaries within the parotid gland, the duct emerges anteriorly from its substance through the adjacent buccal fat, superficial to the masseter muscle over which it passes horizontally 9.

At the anterior border of the masseter muscle, the duct turns medially, making a right-angled turn and pierces the buccopharyngeal fascia (middle layer of the deep cervical fascia) and buccinator muscle. Here it lies in the submucosa of the oral cavity 9.

Within the submucosa, the duct travels a short distance obliquely forwards to open at the papilla, adjacent to the second maxillary molar tooth in the oral vestibule. The oblique submucosal course of the parotid duct acts as a valve, preventing reflux of contents when intraoral pressure increases 8.

Traditionally the parotid duct is described as being approximately 5 cm long and 3mm wide 9. Studies have suggested varying diameters at different points along its length, ranging between 1.4 mm and 0.5 mm, with a maximum of 2.3 mm and a minimum of 0.1 mm, depending on the site 7.

Several other structures run alongside the parotid duct:

It is named after the Danish anatomist Niels Stensen (1638-1686) 2 (also known as Nicolaus Steno) who was the first to describe it, initially in a sheep, in 1660. His colleague Sylvius (1614-1672) confirmed its presence in the human body and van Horne in Leyden named it after Stensen 6

Blockage of the parotid duct can occur secondary to salivary duct stones or external compression. Either cause of obstruction can cause pain and parotitis. Stones are more common in the submandibular gland and duct.

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