the link below gives you the breakdown of all their shelf exams.
http://www.nbme.org/programs/medsch.asp#contout
Here it is for BS...
Progression through life cycle
1%?5%
Psychological and social factors influencing patient behavior
5%?10%
Patient interviewing, consultation, and interactions with the family
10%?15%
Medical ethics, jurisprudence, and professional behavior
5%?10%
Nutrition including vitamin deficiencies and eating disorders
1%?5%
Central & peripheral nervous systems
50%?55%
Normal processes (brain stem, brain, motor systems, autonomic nervous
systems)
5%?10%
Psychopathologic disorders
30%?40%
Principles of therapy and pharmacodynamic general principles
5%?10%
Gender, ethnic, and behavioral considerations affecting
disease treatment and prevention (including psychosocial, cultural, occupational, and environmental)
5%?10%