larval transverse nerve obsolete larval abdominal transverse nerve true FBbt:00002180 Obsoleted as all transverse nerves are abdominal - making this redundant with FBbt:00001996 'larval transverse nerve'. Abdominal transverse nerve that exits the ventral nerve cord at a dorsomedial position, splits into a left and right branch and extends ventrally along the segment boundary (Gorczyca et al., 1994). Formed by the axons of the abdominal intersegmental bidendritic neuron (isbp) and the abdominal intersegmental trachea-associated neuron (istd) (Campos-Ortega, J.A., Hartenstein, V., 1997). larval abdominal TN fly_anatomy.ontology segment boundary nerve