terminal bulb contraction variant C_elegans_phenotype_ontology terminal bulb contraction abnormal Variations in the rhythmic contractions of the posterior pharynx (terminal bulb), such as timing, strength etc. In C. elegans contraction of the terminal bulb inverts the grinder, allowing bacteria in front of the grinder to be broken up and transported to the intestine. WBPhenotype:0000328 pharyngeal contraction variant