Parotid gland

Last revised by Raymond Chieng on 18 Jan 2023

The parotid gland is the largest of the salivary glands and secretes saliva via the parotid duct into the oral cavity to facilitate mastication and swallowing. It is located in the parotid space

The parotid gland is wrapped around the mandibular ramus and extends to a position anterior and inferior to the ear. It has superficial and deep lobes, separated by the facial nerve. Both superficial and deep lobes are connected through an isthmus located behind the ramus of the mandible 13.

The facial nerve and its branches pass through the parotid gland, as does the external carotid artery and retromandibular vein. The external carotid artery forms its two terminal branches within the parotid gland: maxillary and superficial temporal artery 13.

The gland usually contains several intraparotid lymph nodes. These lymph nodes are the first station of lymphatic drainage of the skin of the pinna and peri-auricular skin.

A fibrous capsule surrounds the gland, formed by the superficial (investing) layer of the deep cervical fascia, creating the parotid space. Posteriorly, this fascia condenses to form the stylomandibular ligament.

The inferior projection of the parotid is often referred to as the "tail", which overlies the angle of the mandible. The tail is not distinct from the rest of the gland, but it has been defined as the inferior 2 cm of the gland 11.

Anteriorly, there is often an accessory parotid gland, which may be separate from the main gland.

There is fatty infiltration or fatty replacement of the parotid glands with age 6.

Intraparotid nodes drain into the deep cervical chain. 

  • accessory parotid gland

  • facial process: anterior extension of glandular tissue along the parotid duct continuous with the main gland

  • ectopic parotid tissue

  • parotid duct duplication 7

  • congenital agenesis: either unilateral and bilateral 10

Ultrasound is often the first diagnostic procedure to evaluate morphological and structural changes of the parotid gland; for small (<3 cm) and superficial lesions, ultrasound and cytology are often sufficient for a definitive diagnosis 2.

  • appears homogeneous with increased echogenicity compared to nearby muscle 1

  • intraparotid lymph nodes are normally seen (unlike the submandibular gland)

  • retromandibular vein and external carotid artery are also easily seen and by inference the facial nerve, which lies lateral to these vessels 1

  • limitations of ultrasound are:

    • difficulty visualizing deep lesions: the deep lobe is not able to be assessed as it is protected by the mandibular ramus

    • difficulty visualizing deep extension 3

  • CT and MRI provide useful additional diagnostic imaging if malignancy is suspected 4, with the sensitivity approaching 100% for detecting parotid neoplasms 5

  • the parotid duct and retromandibular vein are usually seen and approximate the plane separating the superficial and deep lobes 12

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1
    Drag here to reorder.
  • Figure 2
    Drag here to reorder.
  • Figure 3
    Drag here to reorder.
  • Figure 4: parotid gland and relations on CT neck (annotated)
    Drag here to reorder.
  • Case 1: facial process (left)
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.