A surgical ligation clip, defining a longitudinal axis and comprising: first and second legs (1501, 1502) each extending along the longitudinal axis and having proximal and distal end portions with respect to said longitudinal axis, a clip hinge joining the first and second legs (1501, 1502) at a point on their respective proximal end portions, the first and second legs each having inner clamping surfaces (1531, 1532) between the clip hinge and the distal end portions of said first and second legs, the clamping surfaces being substantially apposed when the clip is in a fully closed position, a first jaw structure on the first leg extending proximal to the clip hinge, the first jaw structure having a first curved inner surface extending from the clip hinge and facing the longitudinal axis and being substantially concave viewed from said axis, a second jaw structure on the second leg extending proximal to the clip hinge and having a second curved inner surface extending from the clip hinge and facing the longitudinal axis and being substantially concave viewed from said axis, and a buttress body extending from and connected to at least one of the first or the second jaw structure (1541, 1542) by at least a first living hinge extending from said first or second jaw structure, the buttress body having an outer surface, the first and second jaw structures (1541, 1542) being spaced from the longitudinal axis on opposite sides thereof and defining a locking space (170, 1570) therebetween, the buttress body being moveable into the locking space such that at least first and second curved planar segment abutment portions (1551, 1552) of the outer surface of the buttress body each abuts against the substantially concave curved inner surfaces of the first and second jaw structures (1541, 1542) to bias the clip in a closed position, wherein the at least first living hinge connecting the buttress body to at least the first or second jaw structure (1541, 1542) is a laterally spanning web (1560A, 1560B) connecting to a proximal end portion of said buttress body such that, in an unlocked condition, the buttress body is positioned entirely proximal to and spaced from the first and second jaw structures (1541, 1542); wherein the at least first living hinge includes first and second living hinges (1560A, 1560B) each forming a laterally spanning web connecting to the proximal end portion of said buttress body and extending from the first and second jaw structures (1541, 1542), respectively, such that the buttress body tends to be centered on the longitudinal axis outside the locking space and during movement into said locking space; wherein the buttress body forms a substantially cylindrical or generalized cylindrical body spanning laterally on a proximal end of the clip; wherein the locking space is a socket space and a volume subtended by the buttress body can occupy substantially all of said socket space. first and second legs (1501, 1502) each extending along the longitudinal axis and having proximal and distal end portions with respect to said longitudinal axis, a clip hinge joining the first and second legs (1501, 1502) at a point on their respective proximal end portions, the first and second legs each having inner clamping surfaces (1531, 1532) between the clip hinge and the distal end portions of said first and second legs, the clamping surfaces being substantially apposed when the clip is in a fully closed position, a first jaw structure on the first leg extending proximal to the clip hinge, the first jaw structure having a first curved inner surface extending from the clip hinge and facing the longitudinal axis and being substantially concave viewed from said axis, a second jaw structure on the second leg extending proximal to the clip hinge and having a second curved inner surface extending from the clip hinge and facing the longitudinal axis and being substantially concave viewed from said axis, and a buttress body extending from and connected to at least one of the first or the second jaw structure (1541, 1542) by at least a first living hinge extending from said first or second jaw structure, the buttress body having an outer surface, the first and second jaw structures (1541, 1542) being spaced from the longitudinal axis on opposite sides thereof and defining a locking space (170, 1570) therebetween, the buttress body being moveable into the locking space such that at least first and second curved planar segment abutment portions (1551, 1552) of the outer surface of the buttress body each abuts against the substantially concave curved inner surfaces of the first and second jaw structures (1541, 1542) to bias the clip in a closed position, wherein the at least first living hinge connecting the buttress body to at least the first or second jaw structure (1541, 1542) is a laterally spanning web (1560A, 1560B) connecting to a proximal end portion of said buttress body such that, in an unlocked condition, the buttress body is positioned entirely proximal to and spaced from the first and second jaw structures (1541, 1542);