Chiasmatic groove

{{short description|Groove on the sphenoid bone of the skull}}

{{Infobox bone

| Name = Chiasmatic groove

| Latin = sulcus praechiasmaticus,
sulcus chiasmaticus

| Image = Gray145.png

| Caption = ethmoid bone. Upper surface. (Sulcus chiasmaticus labeled at center)

| Image2 = Gray193.png

| Caption2 = Base of the skull. Upper surface. (Sphenoid bone is yellow; chiasmatic groove labeled at center left, fourth from the top of the labels near the yellow region.)

| Origins =

| Insertions =

| Articulations =

}}The chiasmatic groove (chiasmatic sulcus, optic groove, prechiasmatic sulcus) is a transverse{{Cite web |title=chiasmatic sulcus |url=https://medical-dictionary.thefreedictionary.com/chiasmatic+sulcus |access-date=2023-08-01 |website=TheFreeDictionary.com |language=en}} groove upon the superior aspect of the body of sphenoid bone{{Cite book |last=Sinnatamby |first=Chummy S. |title=Last's Anatomy |vauthors= |publisher= |year=2011 |isbn=978-0-7295-3752-0 |edition=12th |pages=}}{{Rp|page=509}} within the middle cranial fossa.{{Rp|page=508-509}} It is bounded anteriorly by the sphenoidal limbus (a variably prominent ridge also representing the posterior boundary of the sphenoidal jugum{{Cite web |title=limbus sphenoidalis |url=https://medical-dictionary.thefreedictionary.com/limbus+sphenoidalis |access-date=2023-08-01 |website=TheFreeDictionary.com |language=en}}), and posteriorly by the tuberculum sellae. The opening of each optic canal is placed at either lateral end of the chiasmatic sulcus. The optic chiasm is situated superior and quite posterior to the chiasmatic groove (and not against the groove as the name suggests).{{Rp|page=509}}File:Chiasmatic groove.jpg