Anatomical structure, which consists of a specific set of the members of (predominantly) one organ or organ part subclass interconnected by zones of continuity or body substances; is demarcated from other subdivisions of the same organ system by one or more zones of continuity or anatomical lines; together with other subdivisions of the same organ system, it constitutes an organ system.

http://www.ifomis.org/hdot/HDOT_CORE_020

Anatomical structure, which consists of a specific set of the members of (predominantly) one organ or organ part subclass interconnected by zones of continuity or body substances; is demarcated from other subdivisions of the same organ system by one or more zones of continuity or anatomical lines; together with other subdivisions of the same organ system, it constitutes an organ system.

http://sig.uw.edu/fma#Organ_system_subdivision

rib cage, facial skeleton, portal system, central nervous system, upper respiratory tract, muscle group of back.

organ system subdivision

hdot:HDOT_CORE_020

organ system subdivision

http://www.ifomis.org/hdot/HDOT_CORE_007