A device for provides access to a surgical location within a patient. The device has an elongate body that has a proximal portion, a distal portion, a first slot segment, and a second slot segment that is angled relative to said first slot segment. The elongate body defines a passage for accessing the surgical location with surgical instruments. The elongate body has a contracted configuration for insertion into the patient and an expanded configuration for providing access to the surgical location. The cross-sectional area of the passage at a first location of the elongate body is greater than the cross-sectional area of said passage at a second location of the elongate body. A movable tab is configured to extend into the second slot segment when the elongate body is in the expanded configuration to retain the elongate body in the expanded configuration.