The hilus is the slit-like opening in the middle of the concave medial border of the kidney. Nerves and blood vessels pass through the hilus into the renal sinus within. Found on http://www.probertencyclopaedia.com/browse/EH.HTM
hilumnoun (anatomy) a depression or fissure where vessels or nerves or ducts enter a bodily organ; `the hilus of the kidney` Found on https://www.encyclo.co.uk/local/20974