What is Ulnar Nerve Entrapment?

As with most nerves, the ulnar nerves (one on each arm) serve very important functions. These nerves run from collarbone to hand, and control many muscle movements the hands perform. When ulnar nerve entrapment occurs, compression or pressure on the nerve limits ability for the hands to move freely and may result in other ongoing symptoms.

There are several symptoms that can arise from ulnar nerve entrapment. One of its hallmarks is numbness/tingling in the pinky finger and half of the ring finger. This “falling asleep” sensation isn’t always present, but it may occur more often if the condition advances. Eventually, ability to grip things could be affected too, and activities performed with the hands may be harder to do. Another symptom of ulnar nerve entrapment is pain at the elbow. This may occur because compression of the nerve most often occurs at the elbow. As the condition progresses, the muscles can become damaged too and decrease in mass (called muscle wasting), and this may further affect the hands and the ability to use them for tasks.

Since the ulnar nerve is so long, there are a number of places on the arm where compression can occur. The most common place is the elbow, on the back side of it where people have the humerus bone. In fact when people hit their funny bone, which is very painful, they are truly making contact with the ulnar nerve. When ulnar nerve entrapment occurs in this area, bending the elbows, leaning bent arms on things like arm rests, and sleeping with the arms bent frequently causes numbness in the pinky finger and ring finger. Compression may also happen near the collarbone, as from injury, or in the wrist, particularly in the section known as Guyon’s canal, which occasionally develops cysts. The exact reason for ulnar nerve compression isn’t always predictable or known in each case, though symptoms typically provide a clue as to location of compression.

It’s possible for people without significant ulnar nerve entrapment to occasionally compress the area when sleeping or leaning on something with a bent elbow for a while, but if the condition begins to occur frequently, people are advised to seek medical help. Doctors may first suggest some minor measures, like avoiding activity when the arms are bent or making sure to keep the arms straight when sleeping. Discomfort felt at the elbow could be treated with non-steroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen.

Physicians may also be able to help patients understand the difference between ulnar nerve entrapment and a somewhat similar condition called carpal tunnel syndrome. This is actually median nerve entrapment but that causes numbness in the hands too. However the area affected is usually the thumb, index finger and middle finger, when numbness is felt.

If symptoms of ulnar nerve entrapment remain unabated, there is concern that muscle wasting can occur and doctors may suggest surgery to open up the compressed area. Surgeries differ depending on area of compression. A surgical approach frequently resolves the issue though it may take some time to recover fully and people may need to participate in physical therapy afterwards so full use or significant use of the muscles affected by the ulnar nerve is restored.