(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.
Position of central sulcus (shown in red). Drawing to illustrate the relations of the brain to the skull. Central sulcus separates the parietal lobe (yellow) and the frontal lobe (blue). Lateral surface of left cerebral hemisphere.Central sulcus is numbered as 6.Medial surface of right cerebral hemisphere. Central sulcus labeled on top center, in red.t is sometimes confused with the medial longitudinal fissure. The central sulcus is a prominent landmark of the brain, separating the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex.