Weber classification of tibial hemimelia based on severity in a higher maturation level. Type I, hypoplasia; type II, diastasis; type III, distal aplasia; type IV, proximal aplasia; type V, bifocal aplasia; type VI, agenesia with double fibula; type VII, agenesia with single fibula. (Type [a] is with cartilaginous anlage and [b] is without cartilaginous anlage; tan represents bone, and blue represents cartilage).