Topics

Topic

design image
Parotid duct

The parotid duct, also known as Stensen’s duct, is the main excretory duct of the parotid gland. It originates from the anterior surface of the parotid gland, courses over the masseter muscle, pierces the buccinator muscle, and opens into the oral cavity opposite the upper second molar tooth. Understanding its anatomy, function, and imaging characteristics is essential for radiologists, ENT specialists, oral surgeons, and dentists, especially when evaluating sialolithiasis, strictures, or tumors.

Synonyms

  • Stensen’s duct

  • Parotid excretory duct

  • Major parotid duct

  • Salivary duct of parotid gland

Function

  • Drains saliva from the parotid gland into the oral cavity

  • Facilitates lubrication of the oral mucosa and digestion initiation

  • Helps maintain oral hygiene and protects oral mucosa

  • Provides a pathway for diagnostic procedures (sialography) and interventions

MRI Appearance

T1-weighted images:

  • The parotid duct is typically low signal relative to surrounding parotid parenchyma.

  • Surrounded by intermediate-signal glandular tissue and high-signal fat in the parotid space, allowing clear duct delineation.

  • Pathologies such as ductal stones may appear hypointense and may cause upstream ductal dilation.

T2-weighted images:

  • The duct itself is hyperintense if filled with saliva, while surrounding parotid tissue is intermediate signal.

  • Ductal dilation, obstruction, or sialadenitis is readily visualized due to high-signal fluid accumulation.

STIR (Short Tau Inversion Recovery):

  • The saliva inside the duct also appears hyperintense, because STIR highlights fluid (not just fat-suppressed edema).

  • Surrounding parotid fat is suppressed, improving contrast.

  • STIR is more useful for detecting inflammation or edema in the gland or peri-ductal soft tissues, rather than the normal duct itself.

CT Appearance

  • The parotid duct appears as a thin tubular soft tissue density structure coursing from the anterior parotid to the oral cavity.

  • Air in the oral cavity adjacent to the duct provides natural contrast on CT.

  • Ductal stones or calcifications are hyperdense and readily visible.

  • Surrounding parotid gland parenchyma is soft tissue density, allowing assessment of glandular enlargement, masses, or inflammation.

  • CT is particularly useful for detecting sialolithiasis, ductal strictures, trauma, or tumor invasion.

MRI images

Parotid ductl axial image -img-00000-00000

MRI images

Parotid ductl sag image -img-00000-00000