Purpose: to verify the occurrence of posterior or submucosal lingual frenulum and evaluate the efficiency of a special maneuver for its visual inspection. Methods: an experimental study including 1,715 healthy infants, in which prematurity, perinatal complications, craniofacial anomalies neurological disorders, and visible genetic syndromes were the exclusion criteria. A clinical examination was performed by means of a maneuver that consisted in rising the lateral margins of the tongue to visualize the anatomical characteristics of the lingual frenulum. In some of the infants, a special maneuver was performed to assist visualization of posterior lingual frenulum, since its visualization was not possible. The maneuver consisted in two simultaneous actions: elevating and pushing the tongue back. Results: 558 infants (32.54%), out of the 1,715 had posterior frenulum, which required the special maneuver that consisted in both elevating and pushing the tongue back, simultaneously. Conclusion: the occurrence of posterior lingual frenulum was high and the special maneuver consisted in elevating and pushing the tongue back proved to be efficient to visualize the posterior lingual frenulum.