Sinus

Sinus may refer to:

Anatomy

In anatomy, a sinus is a cavity within a bone or other tissue. Most are commonly found in the bones of the face and connecting with the nasal cavities.

• Sinus (anatomy), description of the general term.
• Paranasal sinuses, air cavities in the cranial bones, especially those near the nose, including:
  • the maxillary sinuses, also called the maxillary antra and the largest of the paranasal sinuses, are under the eyes, in the maxillary bones.
  • the frontal sinuses, superior to the eyes, are in the frontal bone, which forms the hard part of the forehead.
  • the ethmoid sinuses are formed from several discrete air cells within the ethmoid bone between the nose and the eyes.
  • the sphenoid sinuses are in the sphenoid bone at the center of the skull base under the pituitary gland.
• Anal sinuses are the furrows which separate the columns in the rectum.
• Dural venous sinuses are venous channels found between layers of dura mater in the brain.

In the heart:

• 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;

Other:

• Sinus (botany), a space or indentation, usually on a leaf.

Mathematics

• Sine, a trigonometric math function (Latin sinus)

Astronomy

• Sinus Medii;
• Sinus Successus.

See also

• Hemocoel, a space filled with hemolymph in organisms with open circulatory systems;
• Sines, Portugal, a municipality in Alentejo (Latin Sinus);
• Sinusitis, a common ailment resulting in the inflammation of the paranasal sinuses.

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