dec·us·sa·tion

(dĕk′ə-sā′shən, dē′kə-)

1. A crossing in the shape of an X.

2. Anatomy An X-shaped crossing, especially of nerves or bands of nerve fibers, connecting corresponding parts on opposite sides of the brain or spinal cord.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

de•cus•sa•tion

(ˌdi kəˈseɪ ʃən, ˌdɛk ə-)

n.

1. an instance of crossing or the condition of being crossed in the form of an X.

2. a nerve or tract of nerve fibers that crosses from one side of the central nervous system to the other.

[1650–60]

decussation

the state of being in the form of an X. See also joining.

de·cus·sa·tion

n. decusación, cruzamiento de estructuras en forma de X;

___ of pyramids → ___ de las pirámides, cruzamiento de fibras nerviosas de una pirámide a otra en la médula oblongata;

optic ___ → ___ óptica, cruzamiento de las fibras del nervio óptico.

English-Spanish Medical Dictionary © Farlex 2012

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References in periodicals archive

It has been confirmed using adult rats that unilateral damage in the cerebral hemisphere caused during the juvenile period (when corticospinal tract axons are still forming projections in a caudal direction) allows the corticofugal projection fibers that are descending from the sensorimotor area of the cerebral cortex on the undamaged side to form bilateral axonal projections at each level of the thalamus [14]; striatum [15]; superior colliculus, red nuclei, and pontine nuclei in the midbrain [16]; pyramidal decussation [17]; and spinal cord [18].

Mechanism of Restoration of Forelimb Motor Function after Cervical Spinal Cord Hemisection in Rats: Electrophysiological Verification

[14] reported that, at the neuropathological level, JS results from the hypoplasia and dysplasia of the cerebellar vermis and of pontine and medullary structures, and the absence of decussation of the superior cerebellar peduncles and the pyramidal tracts [24-26].

Physiotherapy and Rehabilitation in a Child with Joubert Syndrome

Indirect pupillary reflexes are not expected in birds because of the complete decussation at the optic chiasm.

Trauma-Induced Uveitis and Free Air in the Anterior Chamber of Three Eastern Screech Owls (Megascops asio)

It has a focal expression at the pyramidal decussation during critical neurodevelopmental stages.

Abnormal subcortical activity in congenital mirror movement disorder with RAD51 mutation

Finally, the pontocerebellar fibers terminate in the cerebellar hemispheres, vermis, and paraflocculus.[3],[9] Based on the special anatomical structures of decussation of fibers in the pons, an infarct in the ventral pons might affect the ipsilateral nuclei, and the tracts that pass to the contralateral MCPs and those passing across from the contralateral nuclei [Figure 5].

Clinical and Radiological Features of Wallerian Degeneration of the Middle Cerebellar Peduncles Secondary to Pontine Infarction

The decussation of the pyramids, which defines the cervicomedullary junction, is estimated by drawing a vertical line across the medulla from the obex of the caudal fourth ventricle.

An Objective Study of Anatomic Shifts in Intracranial Hypotension Using Four Anatomic Planes

Other possibilities include bilateral cortical activation, or that decussation of the cranial nerves, particularly the trigeminal, may be more complex than is currently appreciated [28].

Migraine Pain Location and Measures of Healthcare Use and Distress: An Observational Study

Cervicomedullary stimulation-evoked potentials, which provide a direct measurement of motoneuron excitability by eliciting a single volley in descending axons at the pyramidal decussation, are increased during MI [49].

Change in Reciprocal Inhibition of the Forearm with Motor Imagery among Patients with Chronic Stroke