Pyramid

(pir'-am-id). Any conic eminence an organ, as P. of the cerebellum, P. of the tympanum, etc. Ps., Anterior (of the Oblong at a), the:wo pyramidal bundles of white matter, one on either side of the ventral median fi ure of the medulla. They are continuous with the ventral columns of the ipinal cord, except the decu ating bundles, which are:ontinuous with the deeper portions of the lateral j:olumns of the cord. P. of the Cerebellum, a conic projection forming the central portion of the inferior vermiform proce . Ps.. Cortical. Synonvm of Ps. tig hi. Ps. of Ferrein, a prolongation of the striae of the Malpighian Pyramids into the cortex. rhey are also known as medullary rays. Ps., Giant,: Betz's name for the large pyramidal cells of the cortex i f the para central convolution of the human brain. Lateral. Synonym of Restiform Body. P. of Light, the triangular reflection from the normal membrana tympani. Ps., Malpighian, the conic ma es rom posing the medullary substance of the kidneys. ITiere are from eight to eighteen. Ps., Posterior of the Oblong at a, two narrow bundles of white matter placed one on either side of the dorsal median jti ure of the oblong at a. They are continuous with the dorsal median columns of the spinal cord. al. Shaped ike a pyramid. P. Tracts. See Tracts.