Inconsistent terminology in rodent anatomy hinders appropriate blood sampling in laboratory animal science: A review of blood sampling techniques on the head of mice

Blood sampling is often performed during animal studies. This is more challenging in mice than in larger animal species owing to their size and lack of blood vessel visibility. Guidelines for blood sampling in mice and papers on animal welfare often refer to the submandibular, cheek, buccal, and anterior facial veins. However, these terms are imprecise. There are at least two different superficial veins that can be used for blood sampling on the head of the mouse; moreover, most studies ignore this distinction. Inaccurate descriptions and even incorrect labelling of the images lead to confusion and unnecessary delays in learning blood collection techniques, as well as stress and pain in animals due to failed attempts. This review explains the most common terminological errors, demonstrates the distinction between bleeding facial and superficial temporal veins using original photographs, and discusses the suitability of sampling from both veins.