Ulnar Nerve Neuritis
What is Ulnar Nerve Neuritis?
Ulnar nerve neuritis, also known as ulnar nerve entrapment or cubital tunnel syndrome, is a condition in which the ulnar nerve becomes irritated and inflamed due to constant pressure on it, leading to various symptoms. The nerve can become compressed at several places along its length, such as at the collarbone or wrist; but the most common area of compression is an area of the elbow called the cubital tunnel.
The ulnar nerve travels down the back of the elbow behind a bony bump called the medial epicondyle, and through a passageway called the cubital tunnel. The cubital tunnel is a narrow passageway on the inside of the elbow formed by bone, muscle, and ligaments, with the ulnar nerve passing through its center.
If left untreated, ulnar nerve neuritis can lead to permanent nerve damage in the hand, as well as other conditions such as muscle atrophy (decrease in muscle mass).
Anatomy of the Ulnar Nerve
The ulnar nerve is one of the three major nerves in the arm. It begins in the neck region and passes via the shoulder down the arm into the wrist and fingers. It provides sensation to the forearm and 4th and 5th fingers of the hands. It also regulates most of the small muscles in the hand that assist with fine movement, plus some of the larger muscles in the forearm that assist with grip.
Causes of Ulnar Nerve Neuritis
Some common causes of ulnar nerve neuritis include:
- Injury to the elbow, such as fractures, dislocations, or a direct blow, can cause tissue swelling which can compress the ulnar nerve within the cubital tunnel.
- Individuals who perform repetitive elbow flexion movements at work or play are believed to be at higher risk for developing ulnar nerve neuritis.
- Repeated bending and straightening the elbow can irritate and inflame the ulnar nerve.
- Leaning on the elbow for extended periods of time, such as when working at a desk, can also cause ulnar nerve irritation.
- Bone spurs, ganglion cysts, or tumors can form in the cubital tunnel, leading to pressure and irritation of the ulnar nerve.
Signs and Symptoms of Ulnar Nerve Neuritis
Signs and symptoms of ulnar nerve neuritis usually occur gradually, progressing to the point of requiring medical attention. Commonly reported symptoms associated with ulnar nerve neuritis include intermittent numbness, tingling, and pain to the little finger, ring finger, and the inside of the hand. These symptoms occur more frequently at night, when the elbow is bent or rested upon for prolonged periods.
Diagnosis of Ulnar Nerve Neuritis
Your doctor will assess your symptoms and take your medical history. Specific movements may be performed to physically examine your muscle strength. Gentle tapping at the medial epicondyle region may be performed to observe if you feel sharp sensations in your ring finger and little finger. Imaging studies (X-ray, MRI, CT-scan) may be ordered. Nerve tests including electromyography and nerve conduction studies may be ordered to confirm the diagnosis.
Treatment of Ulnar Nerve Neuritis
Your physician will initially recommend conservative treatment options to treat the ulnar nerve neuritis symptoms unless muscle atrophy or nerve damage is present. Conservative treatment options may include:
- Non-steroidal anti-inflammatory drugs (NSAIDs) to manage swelling and pain.
- Wearing a brace or splint at night while sleeping to keep the elbow in a straight position. You can also wrap the arm loosely with a towel and apply tape to hold it in place.
- Avoiding pressure to the elbow by not leaning on it. Elbow pads may be worn to decrease pressure when working at a desk.
- Physical therapy exercises for strengthening the elbow and arm muscles to enhance your flexibility, range of motion, and strength.
If conservative treatment options fail to resolve the condition or if muscle atrophy or severe nerve compression is present, your surgeon may recommend a surgical procedure to treat ulnar nerve neuritis.
The goal of the surgery is to reduce the pressure on the ulnar nerve by providing more space for the nerve to move freely and to increase blood flow for the inflamed ulnar nerve to heal. Some of the common surgeries performed to treat ulnar nerve neuritis include:
- Medial epicondylectomy: This surgery involves removing a part of the medial epicondyle, the bony bump on the inside of the elbow, and enabling the ulnar nerve to glide smoothly when the elbow is flexed and straightened.
- Ulnar nerve transposition: This surgery involves creating a new tunnel in front of the medial epicondyle and transposing (moving) the ulnar nerve to the new tunnel. This transposition prevents nerve entrapment at the bony ridge and stretching of the nerve when the elbow is bent.
- Cubital tunnel release/ulnar nerve release: This is a procedure to increase the size of the cubital tunnel by trimming and separating the overlying ligament to decrease the pressure on the ulnar nerve and provide more space for the nerve to move freely at the elbow.
- If the ulnar nerve is compressed at the wrist region, your surgeon makes an incision there to access the ulnar nerve and perform nerve decompression in a similar manner.
Your surgeon will decide which surgery is best for you depending on your condition.
The elbow is a complex joint formed by the articulation of three bones – the humerus, radius, and ulna. The elbow joint helps in bending or straightening of the arm to 180 degrees and lifting or moving objects.
The bones of the elbow are supported by:
- Ligaments and tendons
- Blood vessels
Bones and Joints of the Elbow
The elbow joint is formed at the junction of three bones:
- The humerus (upper arm bone) forms the upper portion of the joint. The lower end of the humerus divides into two bony protrusions known as the medial and lateral epicondyles, which can be felt on either side of the elbow joint.
- The ulna is the larger bone of the forearm located on the inner surface of the joint. It articulates with the humerus.
- The radius is the smaller bone of the forearm situated on the outer surface of the joint. The head of the radius is circular and hollow, which allows movement with the humerus. The articulation between the ulna and radius helps the forearm to rotate.
The elbow consists of three joints, namely:
- The humeroulnar joint is formed between the humerus and ulna and allows flexion and extension of the arm.
- The humeroradial joint is formed between the radius and humerus and allows movements like flexion, extension, supination, and pronation.
- The radioulnar joint is formed between the ulna and radius bones and allows rotation of the lower arm.
Articular cartilage lines the articulating regions of the humerus, radius, and ulna. It is a thin, tough, flexible and slippery surface that acts as a shock absorber and cushion to reduce friction between the bones. The cartilage is lubricated with synovial fluid, which further enables the smooth movement of the bones.
Muscles of the Elbow Joint
There are several muscles extending across the elbow joint that help in various movements. These include the following:
- Biceps brachii: Upper arm muscle, enabling flexion of the arm
- Triceps brachii: Muscle in the back of the upper arm that extends the arm and fixes the elbow during fine movements
- Brachialis: Upper arm muscle beneath the biceps, which flexes the elbow towards the body
- Brachioradialis: Forearm muscle that flexes, straightens and pulls the arm at the elbow
- Pronator teres: Muscle that extends from the humeral head, across the elbow, and towards the ulna, and helps to turn the palm facing backward
- Extensor carpi radialis brevis: Forearm muscle that helps in movement of the hand
- Extensor digitorum: Forearm muscle that helps in movement of the fingers
Ligaments and Tendons of the Elbow
The elbow joint is supported by ligaments and tendons, which provide stability to the joint.
Ligaments are a group of firm tissues that connect bones to other bones. The most important ligaments of the elbow joint are the:
- Medial or ulnar collateral ligament: Comprised of triangular bands of tissue on the inner side of the elbow joint
- Lateral or radial collateral ligament: A thin band of tissue on the outer side of the elbow joint
- Annular ligament: Group of fibers that surround the radial head, and hold the ulna and radius tightly in place during movement of the arm
Together, the medial and lateral ligaments are the main source of stability and hold the humerus and ulna tightly in place during movement of the arm.
The ligaments around a joint combine to form a joint capsule that contains synovial fluid.
Any injury to these ligaments can lead to instability of the elbow joint.
Tendons are bands of connective tissue fibers that connect muscle to bone. The various tendons that surround the elbow joint include:
- Biceps tendon: attaches the biceps muscle to the radius, allowing the elbow to bend
- Triceps tendon: attaches the triceps muscle to the ulna, allowing the elbow to straighten
Nerves of the Elbow
The main nerves of the elbow joint are the ulnar, radial and median nerves. These nerves transfer signals from the brain to the muscles that aid in elbow movements. They also carry sensory signals such as touch, pain, and temperature back to the brain.
Any injury or damage to these nerves causes pain, weakness or joint instability.
Blood Vessels Supplying the Elbow
Arteries are blood vessels that carry oxygen-pure blood from the heart to the hand. The main artery of the elbow is the brachial artery that travels across the inside of the elbow and divides into two small branches below the elbow to form the ulnar and the radial artery.