Upper motor neuron (UMN) those neurons that path, they of the brain to the core motor brain stem, or brain neurons, horns, the former the spinal cord to be pulled, etc. applicable.

two main ways of UMN include:

the way of the pyramid or the cortical spinal
the cortical medulla or the way cortical bulbous
the way of the pyramid (Pyramidal Tract), which is the same way can be from the cerebral cortex, starts, and bumps, the pyramid in the medulla oblongata. The majority of fibers, the way the pyramid in the region between the medulla oblongata and the spinal cord to the opposite side of the body can process.

the way of the pyramid, the more the motor neurons, the former (Anterior Motor Neurons) and neurons mediating(Interneurons) in spinal cord termination.

motor neurons former the spinal cord itself, the two types are:

motor neuron Alpha
motor neuron gamma
alpha motor neurons to fibers outside Duki muscle process and so in practice the contraction of skeletal muscles play a role. Gamma motor neurons fibers inside the spindle, the muscle's nerve update. Alpha motor neurons and gamma motor neurons, which in the blade, the ninth of the spinal cord have been influenced by the ways of descending.