part of
connected to
https://github.com/obophenotype/uberon/wiki/Connectivity-Design-Pattern
https://github.com/obophenotype/uberon/wiki/Modeling-articulations-Design-Pattern
a is connected to b if and only if a and b are discrete structure, and there exists some connecting structure c, such that c connects a and b
a 'toe distal phalanx bone' that is connected to a 'toe medial phalanx bone' (an interphalangeal joint *connects* these two bones).
connects
mereotopologically related to
system