Muscular defense is a reflex of the abdominal muscles to contract upon mechanical force to the abdomen, and serves as protection.
It is a visceromotor reflex, since the parietal peritoneum and viscera are involved in generating the reflex.A. V. Livshits. The receptor field of reflex contraction of the muscles of the anterior abdominal wall in man. Bulletin of Experimental Biology and Medicine. Volume 57, Number 4 / April, 1964
See also Abdominal guarding
References
de:Abwehrspannung