What Is Monoplegia and How Does It Affect Your Body?

Monoplegia is a type of paralysis that impacts one limb, most often an arm, but it can also affect one of your legs. Sometimes it can be a temporary condition, but in other cases it can be permanent.

Monoplegia and the nervous system.

Your body has an extensive system of nerves. One of the functions of your nervous system is to move your body’s muscles. This includes movements that you control (voluntary) and those that you don’t (involuntary).

When a part of the nervous system becomes damaged, it can disrupt the signaling activity to a muscle or muscle group. This can lead to muscle weakness (paresis) or paralysis in the affected area.

Damage to the nervous system can include the brain, spinal cord, or one or more nerves, and affect a limb on either the upper or lower part of the body.

Monoplegia symptoms

The symptoms of monoplegia can come on suddenly, as in the case of an injury or stroke. The symptoms may also progress gradually over time due to the progression of cerebral palsy or a motor neuron disease.

The main symptom of monoplegia is the inability to move one of your arms or legs.

You may also experience the following symptoms in or around the affected limb:

• decreased sensation

• muscle stiffness or spasms

• feelings of numbness or tingling

• loss of muscle tone or muscle floppiness

• curling of the fingers or toes on the affected limb

What causes monoplegia?

Monoplegia is often caused by cerebral palsy. It can also be caused by an injury or trauma to the brain, spinal cord, or affected limb.

Other possible, though less common causes, include:

• stroke

• tumors affecting the brain or spinal cord

• peripheral nerve compression, due to conditions like a herniated disc, bone spurs, or a tumor

• nerve inflammation (neuritis)

• peripheral neuropathy

• a motor neuron disease that affects a single limb, such as monomelic amyotrophy

• autoimmune neurological diseases such as multiple sclerosis

Monoplegia vs. hemiplegia

Both monoplegia and hemiplegia are types of paralysis. But how do they differ from each other?

Monoplegia is paralysis that affects a single limb on the upper or lower part of the body. So, for instance if you had monoplegia and couldn’t move your right arm, you would still be able to move your right leg.

Hemiplegia is paralysis that affects one side of the body. Either the right side or the left side of the body can be affected.

If you had hemiplegia on your right side, you wouldn’t be able to move your right arm and right leg. The muscles on the right side of your face might also be affected.

While the two conditions are different, monoplegia and hemiplegia share many of the same potential causes. This can include things like injury, cerebral palsy, and stroke.