decussate

American  

[dih-kuhs-eyt, -it, dih-kuhs-eyt, dek-uh-seyt] / dɪˈkʌs eɪt, -ɪt, dɪˈkʌs eɪt, ˈdɛk əˌseɪt /

adjective

1. in the form of an X ; crossed; intersected.

2. Botany. arranged along the stem in pairs, each pair at right angles to the pair next above or below, as leaves.

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verb (used without object)

decussated, decussating

1. to intersect; cross in the form of an X .

   About 75 percent of these nerve fibers decussate in the medulla.

decussate British  

verb

1. to cross or cause to cross in the form of the letter X; intersect

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adjective

1. in the form of the letter X; crossed; intersected

2. botany (esp of leaves) arranged in opposite pairs, with each pair at right angles to the one above and below it

Other Word Forms

• decussately adverb
• decussation noun

Etymology

Origin of decussate

First recorded in 1650–60; from Latin decussātus “divided in the form of an X” (past participle of decussāre ), equivalent to Latin decuss(is) “the numeral ten,” originally, “a ten-as weight,” supposedly from unrecorded dec(-em) assis ); see origin at ten, as ², -ate ¹

Explanation

Decussate things cross over each other, forming an X shape. In botany, decussate leaves are arranged along a stem in a way that causes pairs of them to overlap each other. You can use decussate as an adjective or a verb — either way, it's a technical term most commonly used by scientists. In anatomy, nerve fibers that cross from one side of the brain to the other are said to decussate, and when rods of tooth enamel decussate, they cross each other in an X shape. Biologists also describe animal and plant markings this way: "I saw the decussate lines on its back and immediately identified the insect!"

Example Sentences

The major differences between the two are in the type of information that is relayed to the brain and where the tracts decussate.

From Textbooks • Jun. 19, 2013

These axons do not decussate in the medulla.

From Textbooks • Jun. 19, 2013

The axons that decussate in the chiasm are from the medial retinae of either eye, and therefore carry information from the peripheral visual field.

From Textbooks • Jun. 19, 2013

Upon reaching the appropriate level, the axons decussate, entering the ventral horn on the opposite side of the spinal cord from which they entered.

From Textbooks • Jun. 19, 2013

As the fibres of the internal capsule run up toward the cortex they decussate with the transverse fibres of the corpus callosum and spread out to form the corona radiata.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" by Various

Related Words

• cross
• cut across