Difference Between UMN and LMN

Neurology is one of the most vital, but extremely complex, studies of the human body, which includes detailed examination of the human brain and its functioning. These are several types of cells, neurons and nerves which constitute of a human brain and as a medical student, or simply someone interested, one must be able to recognise and distinguish between them.

Two of the vital fragments of the human nervous system are UMN (Upper Motor Neuron) and LMN (Lower Motor Neuron). There are a number of differences between these two types of the motor neurons, including their functioning, existence, location etc. You should be able to distinguish between them properly so that their functioning can be understood in a better manner.

The core difference between these two types of neurons is their location and functioning. UMNs, as their name clearly suggests, are located in the upper portion of cerebral cortex of the brain and are responsible for delivering information to other body parts. However, LMNs are located lower down in the motor region and receive information which comes from the UMNs to further distribute it to the body parts, muscles and nerves.

UMNs connect the brain to the spinal cord so that signals are transferred to the other body parts. LMNs are responsible for receiving these signals from UMN and passing them on to the body parts and muscle fibres to ensure proper functioning of every segment of the body.

UMN is a single type of neurons, whereas there are two basic types of LMNs in the nervous system.


  • 1

    Upper Motor Neuron

    The UMN are actually a type of motor neurons, found in the cerebral cortex’s motor region. These neurons are extremely vital in the process of carrying the information from the brain to the other muscles of the body and it is for this purpose, they are attached to the brain stem or the interior horn of the spinal cord.

    Along with other neurons in the nervous system, UMNs deliver information from the brain to the specific parts of the body in form of signals, which are further received by the receptors in the designated areas.

    Image Courtesy: spinalcordconnections.ca

  • 2

    Lower Motor Neuron

    On the other hand, LMNs are found in the main brain stem and constitute to form the spinal and cranial nerves. These LMN nerves are responsible for delivering messages from the brain to the specific parts of the body by passing down chemical signals. These neurons are basically dependent upon the information provided by the UMNs.

    Image Courtesy: arturofbarnes.com

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