Sinus

Sinus may refer to:

Anatomy

In anatomy, where a sinus is a sac or cavity in any organ or tissue:

• 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, in the frontal bone, which forms the hard part of the forehead.
  • the ethmoid sinuses, which are formed from several discrete air cells within the ethmoid bone between the nose and the eyes.
  • the sphenoid sinuses, 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

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 myocardium
• 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

• Several bay-like structures on the surface of the moon:
  • Sinus Aestuum
  • Sinus Amoris
  • Sinus Asperitatis
  • Sinus Concordiae
  • Sinus Fidei
  • Sinus Iridium
  • Sinus Lunicus
  • 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