(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.
Definitions: 1. a longitudinal furrow between the posterior median and the posterolateral sulci of the spinal cord in the cervical region, marking the gracile fasciculus from the cuneate fasciculus.Synonyms: sulcus intermedius posterior, dorsal intermediate sulcus, posterior intermediate groove.The definition information for posterior intermediate sulcus is provided by Stedman's.ynonyms: sulcus intermedius posterior, dorsal intermediate sulcus, posterior intermediate groove. The definition information for posterior intermediate sulcus is provided by Stedman's.