A surgical retractor assembly is provided having a frame that releasably couples two retractor blades. The retractor blades are coupled to the frame via a pair of mobile carriages that engage a track on the frame. A third retractor blade is configured to be independent of the frame with the first two retractor blades. The independent blade may be fixably positionable in the patient by a direct coupling to a rigid table mount. The retractor assembly may be utilized for creating anterior access to spinal target site while the patient is oriented in the lateral decubitus position.