Chiasmatic sulcus

Sulcus chiasmaticus

  • Latin synonym: Sulcus prechiasmaticus; Sulcus praechiasmaticus; Sulcus chiasmatis
  • Synonym: Prechiasmatic sulcus
  • Related terms: Prechiasmatic sulcus

Definition

The chiasmatic sulcus, also known as the suprachiasmatic sulcus or optic groove or prechiasmatic sulcus, is a shallow groove found on the top surface of the body of sphenoid bone. It forms part of the middle section of the floor of the anterior cranial fossa. Right behind this is the hypophyseal fossa, which is separated from the chiasmatic sulcus by the tuberculum sellae, a raised border at the front end of the hypophyseal fossa.

The chiasmatic sulcus leads into the optic canal on each side. Even though the optic chiasma, which is where the optic nerves cross, isn’t located in this groove, it is very close, just behind and above it. This proximity allows the optic nerves to smoothly transition from the optic chiasma to the optic canals, facilitating their journey to the eyes in their sockets.

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

  • Standring, S. (2016). ‘Chapter 28: Intracranial region’ in Gray’s anatomy: the anatomical basis of clinical practice. (41st ed.) New York NY: Elsevier, pp. 430.


Comparative anatomy in animals

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