Barton’s fracture is: (A) Intra-articular fracture distal end radius with carpal bone subluxation, (B) Fracture distal end humerus, (C) Extra-articular fracture distal end radius, (D) Intra-articular fracture distal end radius
Answer is A. Barton's fracture is an intraarticular fracture of the distal radius. 
Here fracture extends from the articular surface of the radius to either its anterior or posterior cortices. 
The small distal fragments get displaced and carry with it the carpals. (carpal bone subluxation) 2 types of volar Bartons fracture and dorsal Bartons fracture. 
Treatment: closed manipulation and plaster cast. when closed reduction fails, internal fixation with plate may be required.