RO:0002170

Binary relationship: x connected_to y if and only if there exists some z such that z connects x and y in a ternary connected_to(x,y,z) relationship.,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

http://www.ncbi.nlm.nih.gov/pubmed/22293552

a 'toe distal phalanx bone' that is connected to a 'toe medial phalanx bone' (an interphalangeal joint *connects* these two bones).

uberon

connected_to

http://purl.obolibrary.org/obo/cl.owl

https://github.com/obophenotype/uberon/wiki/Modeling-articulations-Design-Pattern,https://github.com/obophenotype/uberon/wiki/Connectivity-Design-Pattern,http://purl.obolibrary.org/obo/SIO_000652

connected_to