Wrist Drop

What is wrist drop?

Wrist drop is a term used to describe a type of hand weakness, when the hand tends to fall when the patient tries to lift it up at the wrist joint.

What exactly is the problem in wrist drop?

It is caused by weakness of the muscles on top of forearm and hand. These muscles extend the hand on wrist joint.

What is the cause of wrist drop?

There are numerous causes as the defect may be at any place in the circuitry from the hand to the brain. Some examples are as follows:

1. Muscles: like in muscular dystrophies.
2. Neuromuscular junction: Rare, like in myasthenia gravis, but in that case, it is a generalized condition more than hand weakness.
3. Radial nerve: This is the most common cause. Radial nerve loops around the long bone in arm where it is at risk of compression. For example, a person might be sleeping on a bench with his arm extended and pressed against hard surface of the top of the bench, the so-called Saturday Night Palsy.
4. Brachial plexus: Brachial plexus is the collection of nerves under clavicle. It may be injured due to mechanical trauma, or an alternate cause like viral inflammation.
5. Cervical roots: This is where the nerves originate in the neck. Common cause of a problem is a disc herniation or trauma.
6. Body of motor nerves: Like in motor neuron disease or ALS.
7. Spinal cord: Common causes include multiple sclerosis or an alternate inflammatory lesion, or a tumor.
8. Brain: There are numerous places in the brain where a lesion, like a stroke, MS, or a tumor, may cause hand weakness.

How is wrist drop diagnosed?

Its diagnosis is made by taking history and performing physical examination.

What test is needed to confirm the diagnosis?

In the most common type of radial nerve palsy, testing may not be needed. Otherwise, as there are numerous causes all along the circuitry, a physician tries to figure out the location of problem by doing a thorough examination. Sometimes, examination can be confusing. Choice of test is based upon the suspected location and the cause. As most common cause is radial nerve palsy, an electromyogram (EMG) and nerve conduction studies (NCV) may be ordered to confirm the diagnosis. This test checks the whole circuitry from muscle to the nerve root and the body of the motor nerve. If the cause is suspected in the spinal cord or the brain, imaging studies with an MRI might be needed.

How is wrist drop treated?

Hand is stabilized with a splint, which is available over the counter. Pain, if present, is treated with naproxen type of pain meds. Sometimes a brief course of prednisone is used to control inflammation. Depending upon the exact cause, more specific treatment of the underlying condition may be needed.

What should I do if I have wrist drop or hand weakness?

If it happened suddenly and without any obvious reason, and not more than 24 hours have passed, going to emergency room to be checked for a possible stroke is the best strategy. Otherwise, consult the primary care provider for guidance. A neurological consultation is usually required.

Where can I find more information about wrist drop?

American Academy of Neurology

National Library of Medicine

American Academy of Physical Medicine & Rehabilitation