On the medial wall of the posterior cornu of the lateral ventricle is a longitudinal eminence the calcar avis which is an involution of the ventricular wall produced by the calcarine fissure. For much of the 19th century this ridge was known as the hippocampus minor’It is sometimes visible on ultrasonogram. It can simulate a clot.
This page contains content from the copyrighted Wikipedia article "Calcar avis"; that content is used under the GNU Free Documentation License (GFDL). You may redistribute it, verbatim or modified, providing that you comply with the terms of the GFDL.