The present disclosure describes a surgical access apparatus including an access member with a longitudinal opening defining an internal dimension suitable for removable receipt of a surgical instrument. The access member has a thread mounted thereon that is movable between a first condition and a second condition. When the thread is in the first condition, the access member defines a first outer dimension that allows for positioning of the access member within a tissue tract, and when the thread is in the second condition, the access member defines a second, larger outer dimension to facilitate anchoring of the access member within the tissue tract. As the thread moves between the first and second conditions, the internal dimension of the longitudinal opening extending through the access member remains substantially constant.