grooves

branchial groove pharyngeal groove.

Harrison's groove a horizontal groove along the lower border of the thorax corresponding to the costal insertion of the diaphragm; seen in advanced rickets in childhood.

medullary groove (neural groove) that formed by the beginning invagination of the neural plate of the embryo to form the neural tube.

pharyngeal groove a groove between a pair of pharyngeal arches in a mammalian embryo, homologous to the branchial cleft of a fish, formed by rupture of the membrane separating a corresponding entodermal pouch and ectodermal groove.