Parotid duct

At a glance

English

Parotid duct

Latin (TA2)

Ductus parotideus

System

Digestive

Region

Whole body

Side

Paired, left and right

About the parotid duct

Each parotid gland drains through a single duct, also known by the eponym Stensen's duct. Smaller ducts inside the gland join into one channel that leaves the front border of the gland. It is about 5 to 7 cm long and has a thick wall, so saliva can be pushed along it under pressure.

From the gland the duct runs forwards across the outer face of the masseter muscle, roughly a finger's breadth below the zygomatic arch. Branches of the facial nerve and the transverse facial artery travel alongside it, and a small accessory parotid gland often sits just above it and empties into it. At the front edge of the masseter the duct turns sharply inwards around the buccal fat pad and pierces the buccinator muscle. It then runs a short way forwards under the lining of the cheek before opening on a small papilla in the vestibule of the mouth, beside the upper second molar tooth. The slanting final course acts as a valve: when the cheek is blown out, air pressure squeezes the duct closed.

A useful surface guide is a line from the lower edge of the tragus of the ear to a point midway between the upper lip and the nose; the middle third of that line marks the duct. With the jaw clenched, it can often be rolled under a fingertip against the tight masseter, and its opening can be seen by looking at the inner cheek.

The duct carries the watery, enzyme-rich saliva of the parotid, which is released in large amounts while chewing. Stones are less common here than in the submandibular duct but can block it, causing painful swelling of the gland at mealtimes. Deep cuts to the cheek may sever the duct, and a wound across that surface line should be checked for leaking saliva as well as for facial nerve damage.

Function and supply

Begins at

Formed inside the parotid gland by the union of its interlobular ducts, leaving the gland at its anterior border.

Ends at

Opens on the parotid papilla in the oral vestibule, opposite the upper second molar tooth.

Function

Delivers serous parotid saliva to the mouth, mostly during chewing.

Nerve supply

Lies close to the buccal branches of the facial nerve on the masseter; its own wall receives autonomic fibres with the gland's supply.

Blood supply

Supplied by small branches of the transverse facial artery, which runs just above the duct across the masseter.