Look up sinus or Sinus in Wiktionary, the free dictionary.

Sinus may refer to:

• a sac in front of body worn into a toga, in the typical style of wearing it

• Sinus (anatomy), a sac or cavity in any organ or tissue
  • Paranasal sinuses, air cavities in the cranial bones, especially those near the nose, including:
    • Maxillary sinus, the largest of the paranasal sinuses, under the eyes, in the maxillary bones
    • Frontal sinus, superior to the eyes, in the frontal bone, which forms the hard part of the forehead
    • Ethmoid sinus, formed from several discrete air cells within the ethmoid bone between the eyes and under the nose
    • Sphenoidal sinus, in the sphenoid bone at the center of the skull base under the pituitary gland
  • Anal sinuses, the furrows which separate the columns in the rectum
  • Dural venous sinuses, venous channels found between layers of dura mater in the brain
• Sinus (botany), a space or indentation, usually on a leaf

• Sinoatrial node (sinus node), a structure in the superior part of the right atrium
• Sinus rhythm, normal beating on an ECG
• Coronary sinus, a vein collecting blood from the heart
• Sinus venosus, a cavity in the heart of embryos
• Sinus venarum, a part of the wall of the right atrium in adults, developed from the sinus venosus

• Sinus (Chalcidice), a town of ancient Chalcidice, Greece
• Sinus, gulf or bay in Latin, used in numerous toponyms in ancient writing (e.g., Sinus Magnus, Sinus Flanaticus, etc.)
• Sine, a trigonometric math function (Latin sinus)

• Sinus Medii, a small lunar mare
• Sinus Successus, a lunar feature
• Sines, a municipality in Alentejo, Portugal (Latin Sinus)
• Sinusitis, a common ailment resulting in the inflammation of the paranasal sinuses

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