rubrospinal tract(redirected from Monakow tract)
a somatotopically organized fiber bundle, relatively small in humans, arising from the red nucleus, immediately crossing in the ventral tegmental decussation, and descending near the lateral surface of the brainstem into the lateral funiculus of the spinal cord at the ventral border of the lateral pyramidal tract. It terminates in the zona intermedia of the spinal cord, where its distribution coincides with that of the lateral pyramidal tract; in contrast to the latter, it appears not to have direct connections with spinal motor neurons. Impulses conveyed by this tract indirectly increase flexor muscle tone.
An axon tract originating in the red nucleus of the midbrain. After leaving the red nucleus, axons cross to the contralateral side and descend into the spinal cord, where they terminate in the ventral horns. The red nucleus is innervated by axons from the motor cortices and the cerebellum, and the rubrospinal pathway is an extrapyramidal route to the spinal cord. A major function of rubrospinal axons is to set and adjust the muscle tone in the flexor muscles.
See also: tract
Monakow,Constantin von, Swiss histologist, 1853-1930.
Monakow bundle - Synonym(s): Monakow tract
Monakow fasciculus - Synonym(s): Monakow tract
Monakow fibers - Synonym(s): Monakow tract
Monakow nucleus - a cell group lateral to the cuneate nucleus which receives posterior root fibers corresponding to the proprioceptive innervation of the arm and hand. Synonym(s): accessory cuneate nucleus
Monakow syndrome - contralateral hemiplegia, hemianesthesia, and homonymous hemianopsia due to occlusion of the anterior choroidal artery.