The carpometacarpal joint of the thumb ( pollex ) , also known as the first carpometacarpal joint , or the trapeziometacarpal joint ( TMC ) .
TMC connects the trapezium to the first metacarpal bone .
The carpometacarpal joint of the thumb ( pollex ) , also known as the first carpometacarpal joint , or the trapeziometacarpal joint ( TMC ) because it connects the trapezium to the first metacarpal bone .