Chiasmus. com is a site devoted to cataloging and discussing chiasmatic phrases.    From Wordnik.com.  [Boing Boing: April 13, 2003 - April 19, 2003 Archives] Reference

Behind this is the anterior margin of the chiasmatic groove, running lateralward on either side to the upper margin of the optic foramen.    From Wordnik.com.  [II. Osteology. 5d. The Interior of the Skull] Reference

Behind the chiasmatic groove is an elevation, the tuberculum sellæ; and still more posteriorly, a deep depression, the sella turcica, the deepest part of which lodges the hypophysis cerebri and is known as the fossa hypophyseos.    From Wordnik.com.  [II. Osteology. 5a. 5. The Sphenoid Bone] Reference

The middle part of the fossa presents, in front, the chiasmatic groove and tuberculum sellæ; the chiasmatic groove ends on either side at the optic foramen, which transmits the optic nerve and ophthalmic artery to the orbital cavity.    From Wordnik.com.  [II. Osteology. 5d. The Interior of the Skull] Reference

This surface is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove), above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery into the orbital cavity.    From Wordnik.com.  [II. Osteology. 5a. 5. The Sphenoid Bone] Reference