This surgical retractor has a pair of opposed slat-like sides interconnected at their respective ends with divergence at both ends so that the slats are elastically bowed in arcuate paths with the concave sides of the slats facing each other. Each of the slats has cooperating ratchet and pawl arrangements to permit substantially free lengthwise extension and restricted lengthwise retraction. In one embodiment, the slats are pivotally interconnected at their ends with a ratchet arrangement that permits increase in divergence of the slats and restricts decrease in divergence. In another embodiment, the slats are elastically interconnected at their ends. Extension pieces may be used for varying the size of retractor. An illuminator may be mounted on the retractor as a transparent flexible sterilizable sleeve for surrounding a flexible fiber optic bundle thereby providing illumination from a remote light source. Preferably, the retractor is formed of plastic for disposal after use.