Have you ever experienced a weird tingling sensation after an accidental bump of your elbow against a table? If yes, then you bumped your funny bone!
Children may often complain about arm pain or an electric sensation after hitting the elbow. Although it hurts, the pain usually goes away in a short time. However, if your child has difficulty moving their arms or the pain and tingling sensation lasts for long, it can be due to other causes, and you should seek advice from a pediatrician.
Read this post to know more about the funny bone, the origin of the name, why the funny bone hurts so much, and how to differentiate it from other causes of the tingling sensation in arms.
What Is The “Funny Bone”?
The funny bone is not a bone; it is the part of the ulnar nerve on the back of your elbow and rests against the upper arm bone called the humerus in the elbow. The ulnar nerve originates from the brachial plexus (a network of nerves) in the spinal column (1).
The ulnar nerve provides motor innervation to the parts of the forearm and hand that help move the muscles. The medial side of the forearm, medial wrist, ring finger, and little finger receives cutaneous sensory innervation from the ulnar nerve.
Why Is It Called A “Funny Bone”?
There are two theories why the ulnar nerve in the back of the elbow is called the “funny bone.” Firstly, the name can be a pun since the name of the upper arm bone “humerus” sounds similar to “humorous.” The name could also be due to the peculiar sensation experienced when you bump it into something (2).
Why Does The “Funny Bone” Hurt?
In the elbow, the ulnar nerve lies between the skin and the fat tissue, and the bones do not protect it. Thus, you could be more vulnerable to injuries at this location. When you hit your funny bone, the nerve is stricken and also gets compressed against the bone. Even a small strike on the funny bone can cause pain, numbness, and tingling sensation in the forearm and fingers (3).
Although the elbow is bumped, the tingling sensation can be felt along the course of the ulnar nerve. The strange sensation and pain usually disappear without any complication in most people.
Clinical Significance Of The Ulnar Nerve
An injury to the ulnar nerve at the elbow and wrist can cause the motor and sensory loss of the arms and fingers. The degree of functional loss may depend on the severity of the injury. Trauma, cuts on the wrists, and cyst in the Guyon’s canal (ulnar canal) in the wrists are common reasons for ulnar nerve injuries (4).
Ulnar nerve injuries may cause an inability to grip objects with fingers, and long-term injuries could cause problems, such as ulnar claw hand deformity. The following syndromes can develop due to the entrapment of the ulnar nerve.
- Cubital tunnel syndrome occurs when there is compression or stretching of the ulnar nerve in the elbow region. This may cause pain and a sensation similar to hitting the funny bone, but the symptoms last longer and often feel severe (4).
- Guyon canal syndrome occurs when the ulnar nerve compresses within the Guyon canal or ulnar canal, a canal in the wrist through which the nerve passes. This may cause symptoms such as pins and needles in the ring and little fingers. Overuse of wrist, excessive weight lifting, and trauma are some of the significant causes of this injury (5).
The carpal tunnel syndrome due to median nerve injury may have similar symptoms. Children may not be able to explain the symptoms or the events of injury adequately, and it can be challenging to differentiate between nerve issues. It is recommended to seek expert help for the diagnosis and treatment of nerve injuries.
Signs And Symptoms Of Ulnar Nerve Injury
Knowing the clinical features of ulnar nerve injury could help you differentiate it from self-recovering issues, such as a funny bone hit.
You may notice the following signs and symptoms in ulnar nerve injury (4).
- Pain, numbness, and tingling sensation of the arm
- Sensory loss in the joints of the ring and little finger
- Inability or discomfort while folding thumb and fingers
- Clawing of the ring and little finger
- Loss of muscular bulge on the hand
- Flattening of the medial forearm area
When To See A Doctor
Bumping the funny bone has an impact for a short duration, and it usually gets better on its own. However, if you notice any other symptoms of sensory or motor function impairment in the arm, consult a doctor.
Pain, numbness, and tingling sensation lasting for long could be due to ulnar nerve injuries that require medical care. Doctors can diagnose nerve injuries by assessing the functions of the nerves.
The next time someone asks you, “Which bone in the body never breaks?”, just say “the funny bone.” Sometimes people may use “tickle the funny bone” to indicate the sense of humor in someone. Although it is called the funny bone, bumping on it could cause pain, so do not attempt to locate your funny bone by striking your elbow against the table.
2. Why is it Called the Funny Bone?; New England Baptist Hospital; Beth Israel Lahey Health
3. Everything you ever wanted to know about your funny bone; Healthing
4. Ulnar Nerve Entrapment at the Elbow (Cubital Tunnel Syndrome); The American Academy of Orthopedic Surgeons
5. Dmitri Aleksenko and Matthew Varacallo; Guyon Canal Syndrome; The United States National Library of Medicine
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