Ulnar neuropathy most commonly occurs when the ulnar nerve becomes damaged at the elbow, where it can become compressed as it passes through the cubital tunnel or a variety of other structures. It is also subject to damage with repetitive or prolonged elbow flexion. Much less often, the ulnar nerve can become damaged at the wrist.
The ulnar nerve provides feeling to part or all of the ring finger and the “pinky” finger, as well as that side of the palm. When the ulnar nerve is damaged above the wrist, sensory loss or tingling can also occur on the other side of the hand. Notably, it has no sensory supply above the wrist, such as in the upper arm or forearm (numbness or tingling above the wrist would imply other nerve involvement instead). It also controls most of the hand, involved in gripping items, as well as those that spread the fingers apart, some muscles that flex the ring and pinky fingers, and a muscle that helps flex the wrist.
Damage to the ulnar nerve causes sensory symptoms very similar to those that occur when the “funny bone” is hit. The ulnar nerve lies exposed at the elbow, in between the bones that can be felt there (the humerus and ulna). Depending on the severity, grip strength will be affected, and some patients note that the pinky finger gets caught when trying to put the affected hand into a pocket.
Ulnar neuropathy at the elbow is the second most common compression or entrapment neuropathy, in which one of the body’s peripheral nerves is damaged at a site of vulnerability. Other compression neuropathies median mononeuropathy at the wrist (i.e. carpal tunnel syndrome) or peroneal neuropathy at the head of the fibular bone near the knee.
What are the symptoms of ulnar neuropathy?
What are the symptoms of ulnar neuropathy?Symptoms usually consist of numbness or tingling in the fourth and fifth fingers (ring and pinky fingers). The symptoms often first appear in one or both hands during the night. Patients often will note that they sleepy with the affected arm held bent at the elbow. As symptoms worsen, people might feel tingling during the day, especially with certain activities that involve holding the elbow bent or resting the arm on an armrest. Hand weakness may make it difficult to grasp small objects or perform other manual tasks, such as opening jars. In chronic and/or untreated cases, the muscle in between the thumb and index finger on the top of the hand (first dorsal interosseous muscle) may waste away, causing permanent weakness and loss of hand function.
What are the causes of ulnar neuropathy?
Ulnar neuropathy is often the result of a combination of factors that increase pressure on the ulnar nerve and tendons in the cubital tunnel or elsewhere at the elbow, rather than a problem with the nerve itself. When the elbow is flexed, the nerve must stretch around the structures of the elbow, making it vulnerable to injury with prolonged or repetitive use. Workplace factors may contribute to existing pressure on or damage to the ulnar nerve. The risk of developing ulnar neuropathy is not confined to people in a single industry or job, but may be more reported in those performing assembly line work—such as manufacturing, sewing, finishing, cleaning, and meatpacking—than it is among data-entry personnel.
How is ulnar neuropathy diagnosed?
Early diagnosis and treatment are important to avoid permanent damage to the ulnar nerve.
- A physical examination of the hands, arms, shoulders, and neck can help determine if the person’s complaints are related to daily activities or to an underlying disorder. A physician can rule out other conditions that mimic ulnar neuropathy. A detailed neurological exam will be performed, with particular attention to the sensory and motor functions of the arm and hand.
- Electrodiagnostic tests (EMG/NCV) may help confirm the diagnosis of ulnar neuropathy. In a nerve conduction study, electrodes are placed on the hand and wrist. Small electric shocks are applied and the nerve responses are measured. The ulnar nerve is stimulated at the wrist, below the elbow and above the elbow. If this fails to determine where the ulnar nerve is damaged, it is often helpful to perform an inching study, where small segments of the nerve are stimulated above, at and below the elbow. In electromyography (EMG), a fine needle is inserted into a muscle; electrical activity viewed on a screen can determine the severity of damage to the ulnar nerve and also assess for other conditions which can mimic or occur along with ulnar neuropathy.
How is ulnar neuropathy at the elbow treated?
Treatments for ulnar neuropathy should begin as early as possible, under a doctor’s direction.
Non-surgical treatments:
- Splinting. Initial treatment is usually a splint worn at night to prevent prolonged elbow flexion.
- Avoiding daytime activities that may provoke symptoms. Some people with slight discomfort may wish to take frequent breaks from tasks, to rest the elbow.
- Prescription medicines. Corticosteroids or the drug lidocaine can be injected directly into the elbow.
Surgery
A variety of surgical interventions can be performed for ulnar neuropathy at the elbow. Most traditionally, this involves moving the ulnar nerve (transposition) away from offending structures in the elbow.
