This is a series on arm and hand pain. If you missed the beginning, go back to the “Checklist of Causes.” In my Neuromuscular Therapy center near Boston, I treat arm and hand pain caused by texting and computer use.
The opponens muscles of the little finger and thumb are on the outsides of the hand and do the cupping motion you use to hold a computer mouse or a hand-held texting device like a Blackberry. (See the previous post for the opponens digiti minimi.)
The triangular opponens muscle of the thumb attaches all along it’s long bone from the base of the thumb to the first joint, pulling on the digit from the heel of the hand (attaching to the wrist ligament and trapezium bone). Likewise, the triangular opponens of the 5th finger attaches all along it’s long bone (metacarpal) from the base of the pinkie at the wrist to the first joint and pulls on the finger from the heel of the hand (attaching to the wrist ligament and the pisiform bone). Together, the two opponens muscles work from the opposite sides of the hand (thenar and hypothenar eminences) to bring the metacarpal bones of the thumb and 5th fingers together, cupping the palm to hold an object between the two digits.
Above you see the opponens muscle of the thumb (opponens pollicis) and it’s Trigger Point pattern. Pain from the TrP refers into the palm side of the wrist and up into the thumb itself. The literature doesn’t show specific TrPs for the little finger, but it is safe to assume it has the same pattern as that of the thumb, into the finger and down into the palm side of the wrist. The resulting inner wrist pain can be misdiagnosed as Carpal Tunnel Syndrome.
Self-treatment involves compressing the pad of the thenar eminence between the fingers of the opposite hand and/or pressing the muscle against the bone for 8-12 seconds until a release is felt, then stretching the thumb back and away from the palm. The thenar treatment is shown here on the left. and the stretch on the right.
The hypothenar eminence of the pinkie finger can be treated using the same compression procedure.
The hand-cupping motion of the opponens muscles is assisted by the palmaris longus and palmaris brevis muscles that pull the connective tissue in the palm tight. The next post is on the palmaris longus and brevis.