sinus

sinus definition - medical

si·nus (sīˈnəs)

noun
  1. A depression or cavity formed by a bending or curving.
  2. A channel for the passage of blood or lymph, without the coats of an ordinary vessel, such as the blood passages in the gravid uterus or in the cerebral meninges.
  3. Any of various air-filled cavities in the bones of the skull, especially one communicating with the nostrils.
  4. A dilatation in a blood vessel.
  5. A fistula or tract leading to a pus-filled cavity.

The American Heritage® Medical Dictionary Copyright © 2009 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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