USN: 'An area, subdivision, or region of the body demarcated for the purpose of topographical description.' But the main ontological issue in body regions is their primary status: are they body-parts (objects) or mere regions? Since they can be touched, cut, filled, etc., the intuition goes to the objectual interpretation, but one could think of a special metomymy of medical language: when a body region is at hand, a body part located at that region is at hand, and which one is evident from the operations carried out by physicians and (usually) epistemically shared by them, or by the functions involved in the parts located at the region. On the other hand, if we adopt the regional interpretation, we could have hard times in axiomatizing it: a body region can only exist within an organism (rigidly-depends on it), but cannot be part of it (in fact, UMLS has it as 'conceptual-part'). Currently, we adopt the regional interpretation and axiomatize it by restricting the kind of objects which can be located at body regions.
(Slot-Value-Type Body-Region Crosses-Through Body-Region)
(Slot-Value-Type Body-Region Bearer-Of Medical-Procedure)
(=> (Body-Region ?Self)
(And (Exists (?A)
(And (Location-Of ?Self ?A)
(Anatomical-Structure ?A)))
(Exists (?B) (And (Portion-Of ?Self ?B) (Organism ?B)))
(Exists (?C)
(And (Strictly-Depends-On ?Self ?C) (Organism ?C)))
(Exists (?D) (And (Connected ?Self ?D) (Body-Region ?D)))
(Forall (?E)
(=> (Location-Of ?Self ?E)
(Or (Anatomical-Structure ?E)
(Body-Substance ?E)
(Biologic-Function ?E)
(Body-Region ?E))))
(Exists (?F)
(And (Component-Of ?Self ?F)
(Or (Body-System ?F) (Body-Part ?F))))
(Forall (?G)
(=> (Near ?Self ?G)
(Or (Anatomical-Structure ?G) (Body-Region ?G))))))