“How Big Is a Hand?”, N.D. Rossiter, P. Chapman and I.A. Haywood, Burns, vol. 22, no. 3, May 1996, pp. 230–1 (http://dx.doi.org/10.1016/0305-4179(95)00118-2). The authors, who are at Queen Elizabeth Military Hospital, Woolwich, London, UK, report:
Exactly what constitutes ‘the palm of the hand’ and how large an area this is, depends on whether you follow Advanced Trauma Life Support teaching, United Kingdom teaching, or use a ‘Lund and Browder chart’. A study was designed to measure the areas in question to find which was most accurate. The conclusions challenge standard teaching and show a sex difference. The area of the palm alone is 0.5 per cent BSA in males and 0.4 per cent BSA in females, whereas the area of the palm plus the palmar surface of the five digits is 0.8 per cent BSA in males and 0.7 per cent BSA in females.
(That’s an excerpt from the article “How Big, How Small,” published in AIR 14:5.)