<p>Flatfoot pathologies in adolescents and adults are among the most common deformities of the hindfoot and midfoot. The etiology is multifactorial and often difficult to precisely classify in individual cases, which is why orthotic insoles and foot exercises often remain the only conservative therapeutic measure; however, there are typical clinical presentations that, while not frequently encountered in everyday practice, can lead to misinterpretation and the missed opportunity for important therapeutic interventions. Therefore, this article discusses the Müller-Weiss syndrome, tarsal coalition and instability of the first tarsometatarsal joint. All these conditions share the clinically prominent flatfoot (pes planus) but conservative and surgical treatment approaches differ considerably.</p>