Damages to these structures produce the ipsilateral presentation of paralysis or palsy due to the lack of cranial nerve decussation ( aside from the trochlear nerve ) before innervating their target muscles.
22.
;Chiasm ( also Chiasma ) : Amounts to much the same as "'decussation "', an X-shaped crossing of nerve fibres between the cerebral hemispheres.
23.
Some fibers, termed the anterior external arcuate fibers, emerge from the fissure above this decussation and curve lateralward and upward over the surface of the medulla oblongata to join the inferior peduncle.
24.
About 90 % of these fibers leave the pyramids in successive bundles and decussate ( cross over ) in the anterior median fissure of the medulla oblongata as the " pyramidal decussation " or " motor decussation ".
25.
About 90 % of these fibers leave the pyramids in successive bundles and decussate ( cross over ) in the anterior median fissure of the medulla oblongata as the " pyramidal decussation " or " motor decussation ".
26.
The great majority of the motor outputs from the brain control the opposite side of the body, and the crossings ( decussations ) occur inside the brain, in the midbrain and brainstem . talk ) 20 : 37, 2 December 2010 ( UTC)
27.
Contrast this with a "'Chiasm "'or a "'Decussation "', in which the source and destination of each bundle are not on the same lateral axis, so that the two bundles cross each other obliquely.
28.
The optic nerve leaves the orbit ( eye socket ) via the optic canal, running postero-medially towards the optic chiasm, where there is a partial decussation ( crossing ) of fibres from the temporal visual fields ( the nasal hemi-retina ) of both eyes.
29.
These nerve fibers usually originate in the primary motor cortex, pass via the corona radiata to gather in the internal capsule before crossing over to the opposite side ( decussation ) in the medullary pyramids and proceeding down the spinal cord to meet lower motor neurons in the anterior grey column.
30.
The fibers converge toward the angle of the mouth, where the central fibers intersect each other, those from below being continuous with the upper segment of the orbicularis oris, and those from above with the lower segment; the upper and lower fibers are continued forward into the corresponding lip without decussation.
