One or more refinements may be added to a concept to qualify it. This is done by putting the concept to be qualified before a colon and the qualifying expression after. The qualifying expression is of the form "attribute = value". The example below describes an operation to remove an ovary (i.e. an 'oophorectomy') using a laser.The next example, shown below, describes the right hip joint. Where more than one qualifying attribute is required, these can be separated using a comma. The example below describes the removal of an ovarian structure using a laser device. A further example, below, describes the emergency removal of the appendix: Refinements may also be applied to a conjoined concept . For example, the following two expressions are equivalent (because an 'ulna' is a bone in an 'upper limb'): Note that there are no brackets round " " in the above example, as the refinement automatically applies to the conjoined concept.