The mean size of an inguinal lymph node, as measured over the short-axis, is approximately 5.4 mm (range 2.1-13.6 mm), with two standard deviations above the mean being 8.8 mm. A size of up to 10 mm is generally regarded as a cut-off value for normal vs abnormal inguinal lymph node size.
^Bontumasi, Nicholas; Jacobson, Jon A.; Caoili, Elaine; Brandon, Catherine; Kim, Sung Moon; Jamadar, David (2014). "Inguinal lymph nodes: size, number, and other characteristics in asymptomatic patients by CT". Surgical and Radiologic Anatomy. 36 (10): 1051–1055. doi:10.1007/s00276-014-1255-0. ISSN0930-1038.