zygosphene

from The Century Dictionary.

• noun In herpetology, the wedge-shaped process from the fore part of the neural arch of the vertebræ of serpents and some lizards, which fits into a corresponding fossa, the zygantrum, on the posterior part of the neural arch of a preceding vertebra, and serves thus to interlock the series of arches more effectually than would be done by zygapophyse's alone. Compare cut under zygantrum

from the GNU version of the Collaborative International Dictionary of English.

• noun (Anat.) A median process on the front part of the neural arch of the vertebræ of most snakes and some lizards, which fits into a fossa, called the zygantrum, on the back part of the arch in front.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun anatomy A median process on the front part of the neural arch of the vertebrae of most snakes and some lizards, which fits into a fossa called the zygantrum on the back part of the arch in front.