Point 1 Intro Pathway Deficits Clinical Note Summary Overview Problems Contents  Anatomy

Point 1. Pyramids - Corticospinal Tract The pyramids are two elongated swellings on the ventral aspect of the medulla. Each pyramid contains approximately 1,000,000 CORTICOSPINAL AXONS. As the name implies, these axons arise from the cerebral cortex and terminate within the spinal cord. As corticospinal axons descend from the cortex, they course through the internal capsule, the cerebral peduncle of the midbrain, and the ventral pons (you will learn about these structures later in the course so don't worry about them now). When corticospinal axons reach the medulla they lie within the pyramids. It is important to remember that there has been no crossing yet in this system. The cell bodies of corticospinal axons within the pyramids lie within the IPSILATERAL cerebral cortex.