When people knock their elbow and get a painful tingling or numbness, they often say the have ‘hit their funny bone’. This is Cubital tunnel syndrome or ulnar nerve compression.
Symptoms of Cubital tunnel syndrome come and initially, becoming more persistent over time. They include:
- Tingling or numbness on the outer border of the hand, the little finger and outside of the ring finger.
- Weakness gripping
- Difficulty with tasks requiring fine motor control
- Elbow pain (but not always)
- Partial clawing of the ring and little fingers
Symptoms are often worst at night, waking the patient with tingling sensations in the hand. Prolonged compression results in muscle wasting in the forearm and hand.
The medial epicondyle of the humerus is the bony lump on the inside of the elbow. Some call the medial epicondyle their funny bone. The bony lump at the back of the elbow is the olecranon process. The ulnar nerve runs in the tunnel between these two bones, called the cubital tunnel.
Below the elbow, the ulnar nerve passes into the hand to the little (pinky) and ring fingers, supplying several forearm muscles on its way.
What causes Cubital tunnel syndrome?
Direct trauma or compression of the ulna nerve at the elbow causes Cubital tunnel syndrome. Hitting this spot is acutely tender and produces tingling or shooting sensations.
A number of things cause compression of the ulnar nerve:
- It may be associated with medial epicondylitis (golfer’s elbow).
- Bony spurs which impinge on the nerve
- Arthritis narrows the cubital tunnel
- Cubitus valgus which is an increased angle at the elbow
- Tight bands of fascia over the tunnel
- Leaning on your elbows repeatedly
- Repetitive elbow bending/straightening
- Playing the guitar
- Subluxation (partial dislocation) of the nerve over the medial epicondyle
Cubital tunnel syndrome also occurs following a fracture of the humerus or ulna. This is due to either displaced bone, or swelling causing compression of the nerve.
Rest from aggravating activities such as leaning on elbows, guitar playing and manual work.
Apply ice or cold therapy to help reduce pain and inflammation. A doctor may prescribe anti-inflammatory medication.
A splint may be recommended to keep the elbow still to allow the nerve to heal.
Surgery for Cubital tunnel syndrome is sometimes indicated and involves decompression to release the ulnar nerve.