'Medullary groove' definitions:

Definition of 'Medullary groove'

From: GCIDE

Medullary \Med"ul*la*ry\, a. [L. medullaris, fr. medulla marrow: cf. F. m['e]dullaire.]
1. (Anat.) (a) Pertaining to, consisting of, or resembling, marrow or medulla. (b) Pertaining to the medula oblongata. [1913 Webster]
2. (Bot.) Filled with spongy pith; pithy. [1913 Webster]
Medullary groove (Anat.), a groove, in the epiblast of the vertebrate blastoderm, the edges of which unite, making a tube (the medullary canal) from which the brain and spinal cord are developed.
Medullary rays (Bot.), the rays of cellular tissue seen in a transverse section of exogenous wood, which pass from the pith to the bark.
Medullary sheath (Anat.), the layer of white semifluid substance (myelin), between the primitive sheath and axis cylinder of a medullated nerve fiber. [1913 Webster]