It depends where the person is applying from. There are list of countries in ukba website which tells you if the applicant needs to apply for medical check... In our case my fiance applied from Philippines and he did the tuberculosis test and provided the Tb certificate together with all documents.
Thanks Pultet. I asked because the form attached to the link covers a lot more information than TB. I guess it is left to the discretion of the UKBA officer either at point of application or entry if they want more information on medical history.
Other than TB test, there are no routine medical questionnaires or examinations in connection with your spouse visa applications. When arriving at UK border, if you look visibly ill, they can demand you are checked over by a doctor and you can be refused entry (e.g. if you have contagious disease).