Decussation
Videos
Decussation is used in biological contexts to describe a crossing. In Latin anatomical terms, the form decussatio is used, e.g. decussatio pyramidum.
Decussate phyllotaxis of Crassula rupestris
In this "true bug", Dysdercus decussatus, the specific epithet refers to the bandolier-like markings on the back.
Optic chiasm
Videos
In neuroanatomy, the optic chiasm, or optic chiasma, is the part of the brain where the optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. The optic
Decussation
…examples decussation of pyramids and sensory decussation. In neuroanatomy, the term chiasma is reserved for crossing of- or within nerves such as in the optic chiasm. In botanical leaf taxology, the word decussate describes an opposite pattern of leaves which has successive pairs at right angles to each other (i.e…
Brain viewed from below; the front of the brain is above. Visual pathway with optic chiasm (X shape) is labelled "H" (image from Andreas Vesalius' Fabrica, 1543).
Brain and brainstem seen from below
Left hemisphere of the brain seen in a cadaveric specimen from the side, with the optic chiasm labelled.
Cerebrum, inferior view, deep dissection.