The statement that the fingertips and lips contain the highest density of nerve receptors in the human body is a widely accepted anatomical fact taught in standard biology and does not require a formal literature citation.
The claim refers to basic human anatomical knowledge regarding cutaneous mechanoreceptor distribution (high density in areas like fingertips and lips, corresponding to large cortical representation). None of the retrieved papers directly test or challenge the relative receptor density across all human body parts to evaluate this specific comparative superlative, making it common knowledge rather than a finding dependent on the provided citations.