Pivot joint Pivot joint In animal anatomy, a pivot joint (trochoid joint, rotary joint, lateral ginglymus) is a type of synovial joint. In pivot joints, the axis of a convex articular surface is parallel with the longitudinal axis of the bone. According to one classification system, a pivot joint like the other synovial joint —the hinge joint has one degree of freedom. Note that the degrees of freedom of a joint is not the same as the same as joint's range of motion. Pivot joints allow for rotation, which can be external (for example when rotating an arm outward), or internal (as
The Crooked Hinge The Crooked Hinge The Crooked Hinge is a mystery novel (1938) by detective novelist John Dickson Carr. It combines a seemingly impossible throat-slashing with elements of witchcraft, an automaton modelled on Maelzel's Chess Player, and the story of the Tichborne Claimant. It was dedicated to fellow author Dorothy Sayers "in friendship and esteem." In a poll of 17 detective story writers and reviewers, this novel was voted as the fourth best locked room mystery of all time. "The Hollow Man" also by John Dickson Carr was voted the best. In his ninth outing, Dr. Fell spends July 1937 at a