Definition
Pain between thumb and index finger can severely restrict everyday activities and is therefore a relevant problem. Common causes are muscle strains/overstrains, bleeding, inflammation, abscesses and nerve damage. If the pain persists or worsens, a doctor should always be consulted. Although pain in the hand is usually harmless and lasts only a few days, it may also require treatment or take on a chronic course.
Causes
Pain between thumb and index finger has many, unfortunately rather unspecific causes. Since the thumb and index finger are mainly musculature, nerves and blood vessels, these structures are usually the reason for pain. Frequent causes are muscle irritation, sore muscles, inflammation, nerve entrapment or bleeding.
Bones, ligaments and tendons are rarely the cause of pain because they are directly connected to a single finger and not between two fingers. Carpal tunnel syndrome is the most common nerve compression syndrome. It involves, usually by chance, a relative tightness and entrapment of the “median nerve” under a ligament in the wrist.
The median nerve is one of the larger nerves in the hand and supplies both skin and muscles of the first three fingers (thumb, index and middle finger). Carpal tunnel syndrome causes pain and tingling in the first three fingers, as well as a reduced ability to bend these fingers (loss of strength). The syndrome is treated either conservatively by splinting or surgically by splitting the ligament under which the nerve is constricted.
The ball of the thumb (thenar) is formed by the musculature of the thumb and the so-called “interosseous” (interbone) musculature. An inflammation of the ball of the thumb is therefore usually an inflammation of the muscles. Causes include overloading or irritation of the muscles, a deep wound, migrating bacteria, a traumatic event or autoimmunological causes.
Pain in the ball of the thumb, and thus easy to confuse, is also caused by arthrosis of the thumb saddle joint, rheumatic diseases, arthritis, inflammation of the visual sheath, phlegmons, abscesses, nerve diseases or bleeding. Inflammatory pain is usually permanent and is aggravated by movements and by pressing on the corresponding area. Gentle treatment, cooling and, if necessary, the use of painkillers, for example ibuprofen, can alleviate the pain. If the pain persists, a doctor should be consulted.