The functional significance of the pterygomaxillary ligament in Xenopus Iaevis (Amphibia: Anura)

A pterygomaxillary ligament, which runs postero-inferiorly from the posterior end of the maxilla to the pterygoid, is described macroscopically and microscopically in the aquatic anuran amphibian Xenopus laevis (Daudin). The quadratojugal is absent in this species, and consequently the short maxilla has no posterior articulation and is potentially mobile. However, the pterygomaxillary ligament limits upward and lateral displacement of the maxilla when pressure is applied upwards during closure of the lower jaw. The ligament absorbs forces applied to the posterior end of the maxilla and permits their dissipation via the pterygoid to the neurocranium.