(Botany) an association of a fungus and a plant in which the fungus lives within or on the outside of the plant's roots forming a symbiotic or parasitic relationship. See ectotrophic mycorrhiza, endotrophic mycorrhiza. [C19: from myco- + Greek rhiza root]
Medical Definition of POSTERIOR MEDIAN SULCUS. : a shallow groove along the midline of the posterior part of the spinal cord that separates the two posterior funiculi and is the external boundary of the posterior median septum. a shallow groove along the midline of the posterior part of the spinal cord that separates the two posterior funiculi and is the external boundary of the posterior median septum.
Image: Major Sulci:Central Sulcus Lateral Surface of the Brain For additional information see: HOPES Brain Tutorial Back to Anatomy of the Brain. Function: 1  The central sulcus is the large deep groove or indentation that separates the parietal and frontal lobes.mage: Major Sulci:Central Sulcus Lateral Surface of the Brain For additional information see: HOPES Brain Tutorial Back to Anatomy of the Brain. Function: 1  The central sulcus is the large deep groove or indentation that separates the parietal and frontal lobes.