Variation in parotid gland size, configuration, and anatomic relations

Robbie Medbery, David M. Yousem, Michael F. Needham, Morton M. Kligerman

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Purpose: To examine the variation in the anatomy of parotid glands discerned by magnetic resonance imaging. Methods: Head and neck magnetic resonance scans of 16 patients (representing 32 glands) whose studies consisted of 5 mm contiguous sections were selected at random. The T1 weighted scans were thresholded and outlined to only encompass the parotid tissue. A volumetric analysis program (ISG Technologies, Inc.) was used to compute the parotid volume in cubic millimeters. Each of the 32 glands was measured independently by two observers. Results: The difference between observers averaged 4.8%. The median volume was 25 262 mm3, range 9225-54 080 mm3. In four patients there were considerable differences in the volumes of the right and left parotid glands, with variations of 9, 10, 14 and 29%. In nine patients, (18 glands) the depth from the medial edge of the gland to the spinal cord ranged from 19-32 mm. However, the maximum variation between the two sides in a single patient was 4 mm. Observations made include: (1) parotid glands extending anterior to the masseter muscle, or posterior to the posterior margin of this muscle; (2) parotid glandular tissue extending above the zygoma and the external auditory canal; (3) parotid tissue extending posteriorly to overlap the spinal cord; (4) parotid glands extending below or remaining above the angle of the mandible; and (5) wide variation of the transverse dimension of the parotid glands, with one measuring 4.8 cm. Discussion: To ensure that the entire parotid is or is not in a treatment field a computerized tomography or magnetic resonance scan is necessary. If a specific portion of the gland must be in the field a volume histiogram must be available. Copyright (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish (US)
Pages (from-to)87-89
Number of pages3
JournalRadiotherapy and Oncology
Issue number1
StatePublished - Jan 1 2000
Externally publishedYes


  • Magnetic resonance imaging
  • Parotid gland
  • Parotid variations
  • Radiation therapy
  • Volume histogram
  • Volumetric analysis

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Radiology Nuclear Medicine and imaging


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