मध्यमस्य पुरुषस्य मध्यमाया अनुगुल्या मध्यप्रकर्षो वाङ्गुलम् ॥ कZ_०२.२०.०७ ॥
madhyamasya puruṣasya madhyamāyā anugulyā madhyaprakarṣo vāṅgulam
The vāṅgula is the middle projection (breadth) of the middle finger of a man of medium build.
It attempts to reduce variance in body-based measures by anchoring the reference to an ‘average’ body type, improving consistency in the field.