In 40 hands of adults the ‘loge de Guyon’ a narrow bounded area within the proximal hypothenar region, has been dissected to realize an exact determination of the important characteristics of size. Beside measurements of the wall structures in the region of the pisiform bone, the hook of hamate and the entrances of the loge, variations of muscles and the position of the ulnar artery and nerve with their terminal branches have also been examined.The deep palmar branch of the ulnar artery crosses the rami of the ulnar nerve on the palmar side in 65% of cases. The branch of the artery crosses on the dorsal side in 30% and in 5% the ramus profundus of the ulnar artery runs between both terminal branches of the ulnar nerve. The clinical significance of the loge is emphasized, whereas the irregular nomenclature in the national and international literature is discussed in det