An embryonic structure positioned halfway between the prospective eye and ear, adjacent to the future midbrain-hindbrain boundary. The profundal and the trigeminal ganglia are separate distally but fused at their proximal end as they condense around NF stage 24. [ http://www.ncbi.nlm.nih.gov/pubmed/21452441 https://github.com/obophenotype/uberon/issues/693 ]