A retractor has a proximal portion comprising a first side portion having
a first longitudinal edge and a second side portion having a second
longitudinal edge. The first and second portions being movable relative
to each other such that the first and second longitudinal edges can be
positioned in close proximity to each other or spaced apart by a selected
distance. A distal portion is coupled with the proximal portion. The
distal portion has an outer surface and an inner surface partially
defining a passage. The distal portion is capable of having a
configuration when inserted within the patient wherein the
cross-sectional area of the passage at a first location is greater than
the cross-sectional area of the passage at a second location, wherein the
first location is distal to the second location.