[Location] Localized in the  erect sitting position, on the palm's radialis, the eminentia of thumb's short muscle, at the middle point of first metacarpal bone. (Fig.lOT)
 
[Regional Anatomy] Skin→subcutaneous tissue→short abductor muscle of thumb→opposing muscle of thumb→short flexor muscle of thumb. Superficial layer, the distribution of median nerval ramus cutaneus volaris, and ramus superficialis nervi radialis; deep layer, the distribution of rami musculares nervi mediani and rami musculares nervi ulnaris.