Over dilation

A surgical dilator, comprising:

• an outer tubular member including a slot running along a vertical axis of the outer tubular member and a head portion having a larger outside diameter than an insertion portion of the outer tubular member, said head portion having a guide track;
• and
• an inner tubular member sized to be received within said outer tubular member, said inner tubular member having a protrusion sized to be received within said guide track such that movement of said inner tubular member is restricted by said guide track, wherein said inner tubular member has an upper portion having a generally semi-circular cross-sectional shape along a horizontal axis and a lower portion having a slot, and wherein said inner tubular member is configured to be rotated within said guide track such that in a first position said inner tubular member completely closes off access to said vertical slot, a second position in which said upper portion of said inner tubular member exposes said vertical slot, and a third position in which said vertical slot is entirely exposed.

A surgical dilator, comprising:

• an outer tubular member including a slot running along a vertical axis of the outer tubular member and a head portion having a larger outside diameter than an insertion portion of the outer tubular member, said head portion having a guide track;
• and
• an inner tubular member sized to be received within said outer tubular member, said inner tubular member having a protrusion sized to be received within said guide track such that movement of said inner tubular member is restricted by said guide track, and wherein a lower end of said outer and inner tubular members include an inwardly tapered tip.