Decussatio

Part of speech: noun

Definitions

1. A crossing or intersection of two lines or structures, often seen in anatomical contexts pertaining to the arrangement of nerve fibers
2. The concept of two elements crossing at an angle, especially in a biological or geometrical framework, signifying interconnection
3. An arrangement where two parts intersect, commonly used in reference to the crossing of pathways or fibers within the nervous system

Etymology: "Decussatio" is the Latin word for an intersection shaped like the letter X, and the Romans used it in a fairly literal way. It derives from "decussis," the Roman name for the number ten written as an X (a coin of ten "asses" was marked with it), itself built from "decem" meaning ten and "as," a unit of bronze coinage. So the original sense was almost a numeral symbol, and only later did the idea of two lines crossing take over. Medical writers adopted the Latin term for anatomy, where it describes structures that cross from one side of the body to the other, most famously the nerve fibers of the brain and spinal cord. The term was used in this sense by anatomists in the 17th and 18th centuries, and the crossing it names is the reason one side of the brain controls the opposite side of the body.

Synonyms: crossing, intersection, cruciform, decussation, crosswise