Parasphenoid

The parasphenoid (Os parasphenoidale, Gr. Para = beside, sphenoeides = wedge-shaped), named, is an unpaired covering bones in the skull of vertebrates. In mammals, it has entered into the sphenoid ( sphenoid ).

Originally sets the basisphenoid as a replacement bone, the notochord and the spinal column in the base of the skull to the front ( in the pituitary ) away. Ventral which arises in the throat a tooth- supporting deck bones: the parasphenoid, which by the equally dentate in the body tip, short vomer is continued ( eg still in primitive Teleostei as the Osteoglossiformes Later, the dentition is - as impractical - lost again. ). Through the parasphenoid the basisphenoid is downright repressed and getting smaller, in some fish already missing. The mammals are both merged (mixed bone, called parabasal ) - by receiving the paired Pterosphenoids of fish (the " sphenoid wing ").

Swell

• Dictionary of Biology. Volume 6 p 304 Publisher Herder, Freiburg im Breisgau, 1985, ISBN 3-451-19646-8
• Ihle, van Kampen, Nierstrasz and Verluys (1927 ): Comparative anatomy of vertebrates.