A retractor for retracting the tissue of the body of a patient comprising: a first supporting member, the first supporting member having a first rectangular slot communicating with a first round opening; a second supporting member coupled to said first supporting member for selective translational movement of said-first and second supporting members (20,25) in a direction towards and away from each other; a holding arm connected to said second supporting member on an axis; a first retaining member attached to the holding arm, the first retaining member having a second rectangular slot communicating with a second round opening; a second retaining member attached to the holding arm, the second retaining member having a third rectangular slot communicating with a third round opening; a first lateral blade attached to the first retaining member and a second lateral blade respectively attached to the second retaining member each of said lateral blades (40,50) having a distal end remote from said holding arm, and the lateral blades (40,50) having a first drive screw and a second drive screw attached hereto, wherein operating the first drive screw simultaneously moves the distal ends of each of said lateral blades toward and away from each other in a plane that intersects the direction of the translational movement of said first supporting member and said second supporting members; a medial blade attached to said first supporting member, the medial blade halving a distal end remote from the first supporting member, the retractor being characterized in that: the medial blade has a first post, at least one first flat formed on the first post to allow the first post to slide in the first rectangular slot for quick and easy assembly and disassembly of the medial blade to the first supporting member; and operating the second drive screw simultaneously rotates the distal ends of the lateral blades (40,50) away from the medial blade, the first lateral blade has a second post, at least one second flat formed on the second post to allow the second post to slide in the second rectangular slot for quick and easy assembly and disassembly of the first lateral blade to the first retaining member, and the second lateral blade has a third post, and at least one third flat formed on the third post to allow the third post to slide in the third rectangular slot for quick and easy assembly and disassembly of the second lateral blade to the second retaining member. a first supporting member, the first supporting member having a first rectangular slot communicating with a first round opening; a second supporting member coupled to said first supporting member for selective translational movement of said-first and second supporting members (20,25) in a direction towards and away from each other; a holding arm connected to said second supporting member on an axis; a first retaining member attached to the holding arm, the first retaining member having a second rectangular slot communicating with a second round opening; a second retaining member attached to the holding arm, the second retaining member having a third rectangular slot communicating with a third round opening; a first lateral blade attached to the first retaining member and a second lateral blade respectively attached to the second retaining member each of said lateral blades (40,50) having a distal end remote from said holding arm, and the lateral blades (40,50) having a first drive screw and a second drive screw attached hereto, wherein operating the first drive screw simultaneously moves the distal ends of each of said lateral blades toward and away from each other in a plane that intersects the direction of the translational movement of said first supporting member and said second supporting members; a medial blade attached to said first supporting member, the medial blade halving a distal end remote from the first supporting member, the retractor being characterized in that: the medial blade has a first post, at least one first flat formed on the first post to allow the first post to slide in the first rectangular slot for quick and easy assembly and disassembly of the medial blade to the first supporting member; and operating the second drive screw simultaneously rotates the distal ends of the lateral blades (40,50) away from the medial blade, the first lateral blade has a second post, at least one second flat formed on the second post to allow the second post to slide in the second rectangular slot for quick and easy assembly and disassembly of the first lateral blade to the first retaining member, and the second lateral blade has a third post, and at least one third flat formed on the third post to allow the third post to slide in the third rectangular slot for quick and easy assembly and disassembly of the second lateral blade to the second retaining member.