(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.
Tibialis posterior. The tibialis posterior muscle is a relatively small muscle located within the back side of the calf. It is also the most centrally located muscle in the leg, arising from the inner borders of the fibula and tibia on the posterior (rear) side.he primary function of this muscle is to provide stability to the lower leg. It also facilitates foot inversion (swiveling inward) and aids the ankle's plantar flexion (flexing the foot or toes downward). Additionally, the muscle performs a key role in providing support to the foot's medial arch.