Akademik

a collection of nerve fibres in the central nervous system that extend from the motor cortex in the brain to the spinal cord and are responsible for initiating movement. In the medulla oblongata the fibres form a pyramid (hence the name), within which they cross from one side of the brain to the opposite side of the spinal cord; this is called the decussation of the pyramids. Damage to the pyramidal system manifests in a specific pattern of weakness in the face, arms, and legs, abnormally brisk reflexes, and an extensor plantar reflex (Babinski response).