Finger numbness can significantly affect your ability to perform daily tasks. Normal sensation allows you to type without looking at your fingers, and prevents you from burning yourself or touching a sharp object. Although finger numbness is typically caused by nerve compression, it may be associated with an underlying medical condition. Numbness specifically in the pinkie points to involvement of particular nerves in specific locations. See your doctor to determine the cause and appropriate treatment for your pinkie finger numbness.
Nerve Root Compression
Nerves that supply sensation to your fingers begin at your cervical spine, 7 stacked bones called vertebrae in your neck. Eight pairs of spinal nerves branch off your spinal cord, exiting between your cervical vertebrae. The eighth spinal nerve supplies sensation your outer forearm, including your pinkie finger. Pressure on this nerve may cause numbness in these areas.
Disc herniation and arthritis are the most common causes of nerve root compression in the neck. Bones in your spine are separated by discs. These spongy cushions can move out of position, or herniate, putting pressure on the nerve roots as they exit your spine. Similarly, arthritis causes breakdown of the joints between the vertebrae, decreasing the space for the nerve roots to travel through. Disc herniation or arthritis involving your seventh cervical vertebra increases pressure on the eighth spinal nerve, potentially leading to numbness in your pinkie finger.
Elbow Nerve Compression
Spinal nerve roots branch off into many nerves that provide sensation and power muscles throughout your arm. The ulnar nerve travels along the inside of your elbow, providing sensation to your forearm, ring and pinkie fingers. Bumping your elbow on a hard surface often aggravates the ulnar nerve, causing tingling sensations and temporary numbness in your pinkie finger -- a condition commonly called "hitting your funny bone."
Several factors contribute to long-term compression of the ulnar nerve at your elbow. This nerve travels between muscles and through a tunnel as it runs along the inner elbow. Although the exact cause of nerve compression is not always known, these muscles and tunnel structures can compress the ulnar nerve, causing numbness in your pinkie finger. This nerve can also be damaged with elbow trauma or prolonged pressure on your elbow, which might be caused by resting it on your desk or an armrest, for example.
Wrist Nerve Compression
The ulnar nerve travels along your inner forearm into your hand. This nerve enters your palm on the pinkie side of your hand, travelling through a tunnel called the Guyon canal. Although rare, compression of the ulnar nerve in your hand can cause numbness in your pinkie finger. Tumors, cysts, blood vessel disease and arthritis can increase pressure on the ulnar nerve in the Guyon canal. In addition, the ulnar nerve can be damaged with trauma to this area of your hand. Compression of the ulnar nerve in your hand will not cause tingling in your forearm, distinguishing it from compression at your elbow or neck.
Digital Nerve Injury
Tiny digital nerves -- 2 to 3 millimeters in diameter -- run on each side of your fingers. Damage to one of these nerves can cause numbness in your pinkie, affecting half of the finger on the side where the injury occurred. Digital nerve injuries are typically caused by lacerations or traumatic hand injuries. Surgery is usually required to repair the nerve and restore feeling in your finger with a digital nerve injury.
Numbness in your pinkie finger may be caused by an underlying medical condition. For example, diabetic nerve damage is common in people who have had the disease for many years. Early on, you may have mild tingling and numbness that comes and goes, typically in your fingers or toes. Eventually the affected area may become completely numb. Other medical conditions and certain medications and toxins can also cause finger numbness. However, numbness associated with an underlying medical condition typically occurs in several or all of the fingers rather than just the pinkie.
Pinkie finger numbness can also be caused by a stroke, a potentially life-threatening emergency. Blood clots or blood vessel damage decrease blood flow to your brain. Sudden numbness or tingling in your fingers, particularly on one side of your body, can indicate that you are having a stroke. Seek emergency medical attention if you experience these symptoms.