The<unk>  include both the corticobulbar<unk> and the corticospinal<unk>  These are aggregations of efferent nerve fibers from the upper motor neurons that travel from the cerebral cortex and terminate either in the brainstem (corticobulbar) or spinal cord (corticospinal) and are involved in the control of motor functions of the body. The corticobulbar<unk> conducts impulses from the brain to the cranial nerves. These nerves control the muscles of the face and neck and are involved in facial expression, mastication, swallowing, and other motor functions. The corticospinal<unk> conducts impulses from the brain to the spinal cord. It is made up of a lateral and anterior<unk>  The corticospinal<unk> is involved in voluntary movement. The majority of fibres of the corticospinal<unk> cross over in the medulla oblongata, resulting in muscles being controlled by the opposite side of the brain. The corticospinal<unk> contains the axons of the<unk>  cells, the largest of which are the Betz cells, located in the cerebral cortex. The<unk>  are named because they pass through the pyramids of the medulla oblongata. The corticospinal fibers converge to a point when descending from the internal capsule to the brain stem from multiple directions, giving the impression of an inverted pyramid. Involvement of the<unk> at any level leads to<unk>  signs. The myelination of the<unk>  fibres is incomplete at birth and gradually progresses in cranio-caudal direction and thereby progressively gaining functionality. Most of the myelination is complete by two years of age and thereafter it progresses very slowly in cranio-caudal direction up to twelve years of age.
Pyramidal tracts
Anterior corticospinal tract
Frontopontine fibers
Cerebrospinal fibers
Geniculate fibers
Extrapyramidal system
Striatopallidal fibres
Hypothalamotegmental tract