Here’s a query to find all foreign keys for a table, both keys that reference the specified table, and keys where the table is the child. In SSMS, you can only see the keys for a table where the table is on the child end.

declare @TableName nvarchar(128) = 'Person'

select as TableName, as ReferencedTableName, as ForeignKeyName, f.is_disabled, f.is_not_trusted
from sys.foreign_keys as f
join sys.tables as t
	on t.object_id = f.parent_object_id
join sys.tables as rt
	on rt.object_id = f.referenced_object_id
where = @TableName
	or = @TableName
order by,,