Simple numbness in the right index finger is usually a result of the nerves that innervate it being affected, or it may be a problem with the local blood vessels that supply blood to the index finger, causing a local circulation disorder.
It is more common in daily life to have a right wrist injury, caused by strenuous hand movements, such as swinging a hammer with the wrist or hammering with a fist, which can damage the median nerve that passes through the wrist, a branch nerve that innervates the sensation of the index finger, and when it is damaged, it can cause numbness. Or a blow to the wrist may affect or injure the radial nerve, which also governs sensation in the index finger. Injury to the radial nerve causes decreased sensation and persistent numbness. Further, there is cervical spondylosis, which damages the nerve that innervates the upper extremity, and the distal branch is involved, which simply affects the distal index finger sensation. Peripheral neuritis, where inflammation stimulates the nerve endings and produces lesions that cause abnormal sensation and persistent numbness in the index finger. Long-term diabetes mellitus, which can have complications, metabolic disorders, vascular damage, and oxidative stress that cause peripheral nerve damage, can also cause persistent numbness in the index finger.
Inadequate blood supply to the index finger and poor blood flow cause tingling. In addition, localized bone destruction in the index finger such as osteophytes, rheumatoid arthritis, and fractures cause nerve entrapment, damaging the nerves and producing sensory abnormalities. Anxiety disorder’s may also be anxiety somatization, which can feel persistent tingling of a single finger.