An introducer sheath, comprising: a shaft including a tubular portion, an expandable portion coupled to the tubular portion and a longitudinal axis; wherein the expandable portion includes a first pair of leaflets and a second pair of leaflets, and wherein both the first pair of leaflets and the second pair of leaflets extend along the longitudinal axis; wherein the second pair of leaflets are spaced radially inward of an inner surface of the first pair of leaflets; and wherein the expandable portion is designed to shift between a first configuration and a second expanded configuration; wherein the first pair of leaflets includes a first leaflet (28, 128, 228) and a second leaflet (30, 130, 230), wherein the first leaflet (28, 128, 228) includes a first concave surface extending partially around the longitudinal axis, where the second leaflet (30, 130, 230) includes a second concave surface extending partially around the longitudinal axis and wherein the first concave surface faces the second concave surface; wherein the second pair of leaflets includes a third leaflet (32, 132, 232) and a fourth leaflet (34, 134, 234), wherein the third leaflet (32, 132, 232) includes a third concave surface extending partially around the longitudinal axis, where the fourth leaflet (34, 134, 234) includes a fourth concave surface extending partially around the longitudinal axis and wherein the third concave surface faces the fourth concave surface; characterized in that the third leaflet (32, 132, 232) includes an outer surface and a first rib member disposed along the outer surface of the third leaflet (32, 132, 232), and wherein the fourth leaflet (34, 134, 234) includes an outer surface and a second rib member disposed along the outer surface of the fourth leaflet (34, 134, 234). a shaft including a tubular portion, an expandable portion coupled to the tubular portion and a longitudinal axis; wherein the expandable portion includes a first pair of leaflets and a second pair of leaflets, and wherein both the first pair of leaflets and the second pair of leaflets extend along the longitudinal axis; wherein the second pair of leaflets are spaced radially inward of an inner surface of the first pair of leaflets; and wherein the expandable portion is designed to shift between a first configuration and a second expanded configuration; wherein the first pair of leaflets includes a first leaflet (28, 128, 228) and a second leaflet (30, 130, 230), wherein the first leaflet (28, 128, 228) includes a first concave surface extending partially around the longitudinal axis, where the second leaflet (30, 130, 230) includes a second concave surface extending partially around the longitudinal axis and wherein the first concave surface faces the second concave surface; wherein the second pair of leaflets includes a third leaflet (32, 132, 232) and a fourth leaflet (34, 134, 234), wherein the third leaflet (32, 132, 232) includes a third concave surface extending partially around the longitudinal axis, where the fourth leaflet (34, 134, 234) includes a fourth concave surface extending partially around the longitudinal axis and wherein the third concave surface faces the fourth concave surface; characterized in that the third leaflet (32, 132, 232) includes an outer surface and a first rib member disposed along the outer surface of the third leaflet (32, 132, 232), and wherein the fourth leaflet (34, 134, 234) includes an outer surface and a second rib member disposed along the outer surface of the fourth leaflet (34, 134, 234).