Fracture and dislocation of the base of the first metacarpal

Fracture and dislocation of the base of the first metacarpal bone, also known as Bennett fracture and dislocation, is a very unstable fracture. The thumb carpal metacarpal joint is a saddle-like joint composed of the first metacarpal and most of the horn bones, which is flexible and stable. When the first metacarpal is in a slightly flexed position and is subjected to external force on the longitudinal axis, a fracture line is generated at the base of the first metacarpal from the inside to the outside and obliquely below the joint, forming a triangular bone at the base of the medial base. Piece. This bone mass is generally less than 1/3 of the basal articular surface. Because of the attachment of the collateral collateral ligament, it will continue to maintain a positional relationship with most of the angular bones. Stretching, leading to radial and dorsal dislocations.