Ulnar Nerve Injury

An ulnar nerve injury can cause pain and numbness in your arm. Your arm might also feel weak if you hurt the nerve.

Ulnar nerve injuries can happen from a variety of causes, including accidents and overuse. You can usually treat ulnar nerve injuries by avoiding movements or activities that make your symptoms worse, taking medication for pain, and possibly having surgery.

This article will go over what causes ulnar nerve injuries, how they’re diagnosed, and what your treatment options are.

What Is The Ulnar Nerve?

The ulnar nerve is one of several major nerves that supply the upper extremities (the arms). The ulnar nerve is formed by the nerve fibers in an area around the shoulder blade called the brachial plexus.

When it leaves the brachial plexus, the ulnar nerve travels down the arm. It sends information to some of the muscles of the forearm and hand and gives sensation to parts of the hand.

Symptoms of Ulnar Nerve Injury

If you injure your ulnar never, you may have symptoms of pain, weakness, and abnormal sensation.

Tingling and Numbness

Numbness and tingling (paresthesia) are signs that the ulnar nerve signals are being interrupted.

This can happen when there is pressure or inflammation around the nerve. The location of the paresthesia is not always the same place where there is a problem that is causing ulnar nerve dysfunction.

For example, in the case of cubital tunnel syndrome (the most common location for paresthesia in the hand), the ring and small finger are affected. However, the location of pressure on the nerve is near the elbow joint.

Pain

Pain can be caused by many injuries, but it can be hard to tell if the pain is coming from damage to your ulnar nerve. 

The pain from a nerve condition usually comes with numbness and tingling. It will usually feel like a burning sensation that travels along the path of the nerve. People with nerve pain often described it as shooting or like an electric shock.

Weakness

When nerve function is affected, the brain has a harder time telling muscles to move. As a result, those muscles can get weak. If you hurt your ulnar nerve, you might have trouble doing certain activities or strength maneuvers. 

For example, you may have difficulty pinching or grasping objects. If you have nerve compression that lasts a long time (chronic), the muscles in your arms can waste away (atrophy).

This is generally an irreversible problem and is seen by noting areas where the body has lost its normal muscle mass. People with ulnar nerve injuries can get wasting of the soft tissues in the hand. Holding both hands side by side can make it easier to see signs of wasting.

Ulnar Nerve Injury Causes

Ulnar nerve injuries can happen along any point of the nerve. Sometimes, the damage is from an acute injury, which is sudden and traumatic. 

Other times, ulnar nerve problems come from a chronic, long-standing condition that causes the nerve to stop working over time. 

Cubital Tunnel Syndrome

The ulnar nerve wraps directly behind the humerus bone along the back of the elbow joint. Cubital tunnel syndrome is the chronic compression of the ulnar nerve behind the elbow.

The condition is categorized as compression neuropathy of the upper extremity. It’s the second most common type of compression neuropathy, after carpal tunnel syndrome.

The actual location of compression of the ulnar nerve in people with cubital tunnel syndrome can vary but can include the ligaments, blood vessels, and tendons.

Guyon's Canal Syndrome (Handlebar Palsy)

Guyon's canal, also called the ulnar tunnel, is a location within the wrist that contains the ulnar nerve. Compression of the ulnar nerve in this spot can be from fractures to the small bones of the wrist or ganglion cysts in the wrist.

One of the most common reasons for nerve compression in Guyon's canal is so-called "handlebar palsy.” 

This condition is common in cyclists and happens if the nerve gets pinched against the bones of the wrist and the handlebar of a bicycle, leading to pain and numbness.

If you cycle, you may want to wear padded gloves when you're gripping the handlebars to avoid compression. If padded gloves don't help, changing your grip or changing to a different style of handlebars can often help with numbness and tingling that tend to occur when compression is applied.

Funny Bone

The funny bone is the name people use to describe contusion injuries to the ulnar nerve behind the elbow. In this location, the ulnar nerve wraps behind the arm bone (humerus) just underneath the skin. 

There is very little soft-tissue protection around the ulnar nerve in this location and, as a result, striking this part of the elbow against an object often causes sharp pain, tingling, and numbness along the ulnar nerve. This is the sensation that people describe when they say they "hit their funny bone."

Traumatic Injuries

Traumatic injuries occur as the result of sudden, often violent damage to the nerve. 

Some of the more common mechanisms include nerve contusion (bruising), lacerations, and concussive injuries:

• Nerve contusions typically occur after a fall or motor vehicle collision.
• Lacerations can be caused by injury from broken glass, knife wounds, and other sharp objects.
• Concussive injuries to the nerve can be caused by injuries where the nerve may not be directly damaged by a bullet fragment but get hurt as a result of the concussive force of the gunshot.

How Ulnar Nerve Injuries Are Diagnosed

Nerve injuries can be tough to diagnose, depending on the cause. Finding the location of a nerve injury can be straightforward or more challenging.

The evaluation and treatment of nerve-related conditions is not always a simple one-step visit to a healthcare provider's office.

Sometimes, multiple providers work together to find the source of a nerve injury and determine the best treatment for the cause. 

People with nerve injuries can be seen by their primary care provider, orthopedic surgeons, neurosurgeons, neurologists, physiatrists, or other specialists to help determine the most appropriate treatment for a specific condition.

Your provider will ask you about your symptoms and do a physical exam to diagnose an ulnar nerve injury.

One of the amazing things about the nerves in our bodies is that—except in very rare circumstances—they provide the same patterns of sensation and muscle involvement in just about everyone.

The ulnar nerve very predictably provides sensation in the exact same area for almost everyone: the small finger and half of the ring finger. Knowing these patterns of nerve function can help a skilled provider find the source of the problem.

Tinel's Sign

Many examination techniques are used to isolate and test nerve function. One specific test used to examine people with suspected nerve abnormalities is called Tinel's sign.

A Tinel sign is considered positive when the provider taps directly over the location of nerve abnormality and it re-creates symptoms of paresthesia and discomfort along the path of the nerve rather than at the specific location where the tapping takes place.

For example, a positive Tinel's sign in a patient with cubital tunnel syndrome would, by tapping behind the elbow joint directly over the ulnar nerve, re-create symptoms of paresthesia and pain in the ring and small fingers.

Other Tests

Other tests can be done to assess the ulnar nerve and the surrounding anatomy which could be causing compression or injury to the ulnar nerve. 

• A regular X-ray can check for deformities of the bone, bone spurs, or other abnormal structures that could be causing irritation to the ulnar nerve.
• Other imaging tests, including MRIs and CT scans, are less commonly used but can be helpful if there is a concern for a possible cause such as a ganglion cyst, tumor, or other soft tissue mass that could be causing compression on the nerve.
• High-resolution ultrasound is being used more frequently because it is noninvasive and relatively quick and easy to do. However, ultrasound examinations are highly dependent on technician experience, and not every facility has the capability to look at a patient’s ulnar nerve with ultrasound. 
• Electrical studies of the nerve include the measurement of nerve conduction and electromyography (EMG).

While these studies can be helpful in finding the source of a nerve condition, they can be uncomfortable for the patient since they involve placing needles into the skin and measuring an electrical current along the path of the nerve.

Treatment for Ulnar Nerve Injuries

The only way to treat an ulnar nerve injury successfully is to figure out exactly where the problem is. This may sound straightforward, but the symptoms of the nerve injury are often not felt at the location of the damage to the nerve.

Trying to determine the location of the problem often takes some time and testing, but these steps need to happen before a treatment can be decided on.

Treatment for an ulnar nerve injury might include:

• Avoiding specific activities that put pressure on the nerve
• Immobilization to limit movement of the nerve
• Padding for protection to keep pressure off of the nerve

If a component of the compression on the nerve is the result of inflammation, treatments that reduce inflammation can be helpful.

These treatments commonly include:

• Topical anti-inflammatory measures (ice application)
• Oral anti-inflammatory medications (nonsteroidal anti-inflammatory medications)
• Steroid medications (including oral medications or cortisone injections)

Surgical treatments for ulnar nerve problems depend on the type of injury. When there is a direct injury to the nerves, such as a laceration, these injuries are often fixed soon after the injury. 

If there is a broad area of damage to the nerve, nerve grafting may have to be done to reconnect healthy portions of the nerve. When there is compression on the nerve, surgical solutions are aimed at relieving the pressure and removing tension from the nerve.

In some cases, this just requires removing pressure on the nerve in a minimally invasive surgical procedure. In other cases, it involves relocating the position of the nerve so that there is less tension on it.

A common treatment for people with cubital tunnel syndrome is to move the nerve from the back of the elbow to the front (ulnar nerve transposition). In the new position, the nerve is no longer under a lot of tension when the elbow is bent.

Summary

If you injury your ulnar nerve, you may have pain, numbness, tingling, and weakness in your arm. It can be tricky to find out the cause of the injury because the symptoms you have may not be exactly where the problem is. Your provider can use different tests to figure out the source of the problem and recommend the appropriate treatment.