A torque device configured to accommodate a guidewire that is to be inserted into the vasculature or other physiological location of a patient, the torque device configured to engage the guidewire when the guidewire is positioned within the vasculature of the patient in a manner that a practitioner can manipulate the guidewire with a single hand by grasping and manipulating the torque device, the torque device comprising: a housing having an outer periphery and including a portion of a lumen of the torque device which is configured to allow passage of the guidewire; and an actuator operably connected to the housing, the actuator defining an actuator portion of the lumen which is configured to allow for selective engagement of the guidewire, such that when the actuator is in a first position, the guidewire is secured relative to the torque device, and when the actuator is in a second position, the guidewire can be moved relative to the torque device, wherein, the housing defines a distal portion of the lumen that includes an upper wall surface and a lower wall surface and defines a proximal portion of the lumen that includes an upper wall surface and a lower wall surface, and the actuator portion of the lumen includes an upper wall surface and a lower wall surface and the upper wall surface is continuous with the lower wall surface through the actuator portion of the lumen; characterized in that the proximal and distal housing portions (25, 23) of the lumen and the actuator portion of the lumen are non-circular in transverse cross-section, having a larger cross-sectional area at one end and a more narrow cross-sectional area at an opposite end such that when the actuator is in the first position, the actuator portion of the lumen contacts at least two elongated areas of the guidewire at the more narrow cross-sectional area and each of the proximal and distal housing portions (25, 23) of the lumen contacts at least two elongated areas of the guidewire at the more narrow cross-sectional area, wherein, the larger cross-sectional area and the more narrow cross-sectional area of the actuator portion of the lumen are inverted relative to the larger cross-sectional area and the more narrow cross-sectional area of the proximal and distal housing portions (25, 23) of the lumen such that when the actuator is in the first position, the more narrow cross-sectional area of the actuator portion of the lumen is aligned with the more narrow cross-sectional areas of the proximal and distal housing portions (25, 23) of the lumen. a housing having an outer periphery and including a portion of a lumen of the torque device which is configured to allow passage of the guidewire; and an actuator operably connected to the housing, the actuator defining an actuator portion of the lumen which is configured to allow for selective engagement of the guidewire, such that when the actuator is in a first position, the guidewire is secured relative to the torque device, and when the actuator is in a second position, the guidewire can be moved relative to the torque device, wherein, the housing defines a distal portion of the lumen that includes an upper wall surface and a lower wall surface and defines a proximal portion of the lumen that includes an upper wall surface and a lower wall surface, and the actuator portion of the lumen includes an upper wall surface and a lower wall surface and the upper wall surface is continuous with the lower wall surface through the actuator portion of the lumen; characterized in that the proximal and distal housing portions (25, 23) of the lumen and the actuator portion of the lumen are non-circular in transverse cross-section, having a larger cross-sectional area at one end and a more narrow cross-sectional area at an opposite end such that when the actuator is in the first position, the actuator portion of the lumen contacts at least two elongated areas of the guidewire at the more narrow cross-sectional area and each of the proximal and distal housing portions (25, 23) of the lumen contacts at least two elongated areas of the guidewire at the more narrow cross-sectional area, wherein, the larger cross-sectional area and the more narrow cross-sectional area of the actuator portion of the lumen are inverted relative to the larger cross-sectional area and the more narrow cross-sectional area of the proximal and distal housing portions (25, 23) of the lumen such that when the actuator is in the first position, the more narrow cross-sectional area of the actuator portion of the lumen is aligned with the more narrow cross-sectional areas of the proximal and distal housing portions (25, 23) of the lumen.