Ulnar Nerve (Funny Bone)

What is your ulnar nerve?

Your ulnar nerve helps you move your forearm, hand, and fourth and fifth fingers. Your forearm extends from your elbow to your hand. Your ulnar nerve also sends sensory information like touch, temperature and pain to your brain. This nerve is commonly known as your funny bone.

Pressure on your ulnar nerve can lead to certain health conditions that cause pain, numbness and weakness in your hand, arm and elbow. This can affect the way you grip items, perform daily tasks and even feel sensation. If you experience any of these symptoms, reach out to your healthcare provider. They’ll talk to you about what you’re feeling and provide solutions to make you feel better.

Why is it called a funny bone?

Your ulnar nerve runs underneath the first layer of skin near your elbow. When you bump your elbow against a hard surface, you may temporarily pinch your ulnar nerve. The impact causes a funny-feeling, shock-like tingling or burning known as “hitting your funny bone.”

What is the purpose of your ulnar nerve?

Your ulnar nerve controls nearly all of the small muscles in your hand. Although your ulnar nerve begins at your armpit, it doesn’t perform a function until it enters your forearm.

As a motor (movement) nerve, your ulnar nerve stimulates muscles in your forearm, hand and fingers so you can:

• Bend and straighten your pinky and ring fingers
• Grip and hold items
• Perform fine motor tasks, like writing with a pen, buttoning a shirt or turning pages in a magazine

As a sensory nerve, your ulnar nerve gives feeling to your:

• Pinky finger
• Ring finger on the side closest to your pinky finger
• Palm and back of your hand on the pinky side

Where is your ulnar nerve?

Your ulnar nerve is one of five nerve branches of your brachial plexus. This nerve bundle sends sensory information and helps you move your shoulders, arms and hands.

Your brachial plexus starts as nerve roots in the cervical spine in your neck. These nerves then go behind your collarbone (clavicle), through your armpit (axilla) and down your arm.

You have a left and right ulnar nerve — one to serve each arm. Your ulnar nerve starts at the brachial plexus in your armpit and:

• Connects to your C8 cervical vertebra and T1 thoracic vertebra (the middle of your brachial plexus)
• Runs down the front of your upper arm near your axillary and brachial arteries
• Travels through your cubital tunnel, a tissue opening located under a bony bump in your elbow (medial epicondyle)
• Goes beneath muscles on the inside of your forearm, running alongside your median nerve and your ulna (the long bone in your forearm)
• Divides into smaller nerve branches
• Enters your palm on the pinky finger side through an opening called Guyon’s canal (ulnar tunnel) that also holds your ulnar artery

What are your ulnar nerve branches?

Your ulnar nerve branches include:

• Muscular branch. Controls movement in the front of your forearm.
• Dorsal cutaneous branch. Sends sensory information between your brain and the middle back of your hand, pinky finger and ring finger.
• Palmar cutaneous branch. Sends sensory information to and from the middle part of your palm and pinky and ring fingers.

What conditions and disorders affect your ulnar nerve?

Conditions and disorders that can affect your funny bone nerve include:

• Ulnar nerve entrapment. Pressure on the ulnar nerve in your elbow or wrist can cause a pinched nerve, nerve (neuropathic) pain and/or neuropathy (nerve damage).
• Cubital tunnel syndrome. Prolonged pressure affects your ulnar nerve inside the cubital tunnel in your elbow.
• Ulnar tunnel syndrome (Guyon’s canal syndrome). Pressure on your ulnar nerve inside the Guyon’s canal in your wrist causes symptoms similar to carpal tunnel syndrome.
• Ulnar nerve dislocation. Your ulnar nerve stretches and slips out of place, often after a traumatic injury. You may feel or hear a snap in your elbow.

What are the signs of ulnar nerve problems?

Signs of a pinched ulnar nerve may include:

• Curvature of your pinky and ring fingers (claw hand)
• Elbow pain or wrist pain
• Hand weakness that affects your ability to grasp items or perform tasks like writing or typing
• Muscle loss in your hand and affected fingers (a rare symptom)
• Numbness or tingling in your pinky finger and ring finger

When should I talk to a healthcare provider?

You should call your provider if you experience:

• Curving inward of your ring finger or pinky finger
• Loss of grip strength or inability to grasp items
• Pain, numbness or tingling sensation in your elbow, wrist, pinky finger or ring finger
• Problems performing tasks like buttoning a shirt or writing