{"action":"opened","issue":{"url":"https://api.github.com/repos/obophenotype/human-phenotype-ontology/issues/499","labels_url":"https://api.github.com/repos/obophenotype/human-phenotype-ontology/issues/499/labels{/name}","comments_url":"https://api.github.com/repos/obophenotype/human-phenotype-ontology/issues/499/comments","events_url":"https://api.github.com/repos/obophenotype/human-phenotype-ontology/issues/499/events","html_url":"https://github.com/obophenotype/human-phenotype-ontology/issues/499","id":104769059,"number":499,"title":"subclass modeling of arterial branches","user":{"login":"markengelstad","id":6233351,"avatar_url":"https://avatars.githubusercontent.com/u/6233351?v=3","gravatar_id":"","url":"https://api.github.com/users/markengelstad","html_url":"https://github.com/markengelstad","followers_url":"https://api.github.com/users/markengelstad/followers","following_url":"https://api.github.com/users/markengelstad/following{/other_user}","gists_url":"https://api.github.com/users/markengelstad/gists{/gist_id}","starred_url":"https://api.github.com/users/markengelstad/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/markengelstad/subscriptions","organizations_url":"https://api.github.com/users/markengelstad/orgs","repos_url":"https://api.github.com/users/markengelstad/repos","events_url":"https://api.github.com/users/markengelstad/events{/privacy}","received_events_url":"https://api.github.com/users/markengelstad/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-09-03T19:52:13Z","updated_at":"2015-09-03T19:52:13Z","closed_at":null,"body":"when dealing with entities like 'abnormality of facial artery', what should be its superclass? \r\n\r\nAlthough the facial artery is a branch of the external carotid artery, its not ontologically proper to say the 'Abnormality of facial artery' is_a 'Abnormality of external carotid artery', so it doesn't seem right that 'Abnormality of facial artery' should be a subclass of 'Abnormality of external carotid artery' -- yet it's appealing to model it that way given the branching nature of arteries and veins. \r\n\r\nso, if 'abnormality of facial artery' isn't a subclass of 'abnormality of external carotid artery', then what should it be a subclass of?  \r\nAbnormality of carotid arteries?\r\nAbnormality of the systemic arterial tree?\r\n\r\nOr would it be proper to create a class:  'Abnormality of branch of external carotid artery' ? "}}