The peripheral nervous system is a nerve network that provides sensation and fine movement to the limbs and extremities. Any damage or injury to a nerve in the peripheral nervous system can cause abnormal sensations such as numbness in the pinky fingers. Numbness can also develop from a lack of proper blood flow to the extremities.
Raynaud's Phenomenon
The arteries, which are the largest blood vessels in the body, are responsible for carrying blood to the heart from other areas of the body. The arteries constrict and dilate at specific times to ensure efficient and proper blood flow to the heart. Raynaud's phenomenon is a condition that occurs when the arteries constrict in abnormal circumstances, cutting off blood supply to the fingers, toes and, occasionally, the nose. These episodes of spontaneous constriction are called vasospasm and are usually triggered by cold temperatures or times of increased stress. When the arteries constrict, blood flow is reduced, which causes the fingers and toes to turn white and feel numb, cold and painful, according to the National Heart, Lung and Blood Institute. As normal blood flow returns, the fingers and toes will turn red and begin to tingle or throb. There is no cure for Raynaud's phenomenon. The National Heart, Lung and Blood Institute states that preventing attacks, by avoiding cold temperatures, keeping the hands warm and engaging in stress reducing activities, is the best treatment method.
Ulnar Nerve Entrapment
Ulnar nerve entrapment is a condition in which the ulnar nerve in the arm becomes compressed. The ulnar nerve runs from under the collarbone, through the outside of the elbow and down into the smallest two fingers of the hand. It provides sensation to the ring finger and pinky finger and controls the muscles that allow fine movement. Compression of the ulnar nerve usually occurs at the elbow, but can happen anywhere along the length of the nerve. Several factors, including bone spurs, prior fractures, cysts and inflammation of the elbow joint, are thought to contribute to ulnar nerve entrapment. When the ulnar nerve is compressed, it affects normal sensation as well as movement. Those with ulnar nerve entrapment will experience numbness and tingling in the ring and pinky fingers, pain in the elbow, difficulty with finger movement and weak grip, according to the American Academy of Orthopaedic Surgeons. Most cases can be treated with immobilization of the joint and over-the-counter medications. In severe cases, surgery may be needed to relieve the pressure on the nerve.
Carpal Tunnel Syndrome
The carpal tunnel is a narrow passageway that protects one of the main nerves in the arm, the median nerve, as well as a number of tendons that bend the fingers. Carpal tunnel syndrome occurs when the carpal tunnel exerts an increased amount of pressure on the median nerve, compressing it. One of the most common causes of carpal tunnel syndrome is inflammation of the carpal tunnel due to repetitive wrist movement, such as typing, according to MayoClinic.com. A genetically small carpal tunnel or chronic disorders can cause some cases of carpal tunnel. Symptoms of carpal tunnel include tingling and numbness in the fingers and hand; pain in the hand and arm; weakness in the hand and decreased grip strength. Most cases of carpal tunnel syndrome can be effectively treated with medications and splinting of the wrist. If symptoms are severe, surgery may be needed.
