Sinus of sphenoid bone

Sinus ossis sphenoidei

  • Latin synonym: Sinus sphenoideus osseus; Sinus sphenoidalis
  • Synonym: Bony sphenoidal sinus; Sphenoid sinus
  • Related terms: Sphenoidal sinus

Definition

The sphenoidal air sinuses (a.k.a. sinus of sphenoid bone) are a pair of air filled spaces located within the body of sphenoid bone. The sphenoid air sinuses play a part in forming the roof of the nasopharynx and are situated behind the upper part of the nasal cavity. This positioning allows surgeons to access the pituitary gland through the nasal cavity. The procedure, known as the transsphenoidal approach, involves drilling a hole through the sphenoid sinus, breaking through the sella turcica, and gaining access to the pituitary gland.  

The sphenoid bone’s right and left sinuses are separated by a bony septum in the center. Both sinuses are irregularly shaped, usually of different sizes, and can be further divided into subcompartments by bony laminae. Each sphenoid air sinus has an opening in its front upper wall, which lets the sinus drain into the sphenoethmoidal recess found just above the superior nasal concha, in the upper lateral wall of the nasal cavity.

Position-wise, each sinus of sphenoid bone is related superiorly to the optic chiasma and hypophysis cerebri (pituitary gland), while laterally it is related to the cavernous sinus and the internal carotid artery.

The sphenoid air sinuses receive their arterial supply from the posterior ethmoidal branches of the ophthalmic artery and the nasal branches of the sphenopalatine arteries. Their venous blood is drained through the posterior ethmoidal vein, and their lymphatics drain into the retropharyngeal lymph nodes. Nerve supply is provided by the posterior ethmoidal nerves, which handle general sensation, and the orbital branches of the pterygopalatine ganglion, which are responsible for parasympathetic secretomotor nerves.

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Text written by Muhammad A. Javaid, MD, PhD © 2024 IMAIOS.

  • Standring, S. (2016). ‘Chapter 33: Nose, nasal cavity and paranasal sinuses’ in Gray’s anatomy: the anatomical basis of clinical practice. (41st ed.) New York NY: Elsevier, pp. 568.


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