Dictionary.net

As described by J. Muller, are short vessels given off from the larger branches, as well as from the finest twigs of the artery of the organ: most of those come off at a right angle, and project into the cavity of the spongy substance, either terminating abruptly or swelling out into a club-like process without again subdividing. Almost all these vessels are bent like a horn, so that the end describes half a circle or somewhat more. They have a great resemblance to the tendrils of the vine, whence their name. A minute examination of them, either with the lens or the microscope, shows that, although they at all times project into the venous cavities of the corpora cavernosa, they are not entirely naked, but are covered with a delicate membrane, which, under the microscope, appears granular.