FIGURE 33b - Extrapyramidal Pathways

Intro

Figure 33a:	Fibers from Cerebral Cortex | Upper Level of the Medulla | Lower Level of the Medulla | Spinal Cord
Figure 33b:	Cerebral Hemisphere | Midbrain | Medulla and Cerebellum | Spinal Cord
Figure 33c:	Ventromedial Corticospinal Tract | Ventromedial Cortico-Brainstem-Spinal Tract

Part 1: Image-Mapped Tutorial
Part 2: Matching Self-Test: 33a | 33b | 33c
Part 3: Multiple-Choice Self-Test

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2 - Midbrain

The red nucleus of the extrapyramidal system lies within the midbrain and receives projections from both the primary motor cortex (via the corticorubral tract) and the cerebellum. Axons descending from the red nucleus cross to the contralateral side of the nervous system at the level of the medulla (via the rubrospinal tract). After crossing, this portion of the extrapyramidal system projects to the interneurons of the spinal cord. Together the corticorubral tract and the rubrospinal tract make the corticorubrospinal tract. The information conveyed via the corticorubrospinal tract controls the contraction of distal muscles of the arms and legs, and thus affects movement of the forearms, hands (but not fingers) and feet.