According to Medicinsk-Odontologisk ordbog:

registrar (Registrars are adressed as Doctor or Mr X, Miss or Mrs Y according to whether they are medical or surgical)
[a registrar is a senior house officer. The registrar will practically always have a higher qualification than house officers. A ‘surgical registrar’ will do the routine surgery for example, appendicectomy, hernia etc, without the supervision of a more senior surgeon but he will only perform major operations with a more senior surgeon present]

http://ordbog.gyldendal.dk/sitecore/content/Ordbog/Home/Opsl...

There are more details if you look up the entry in full, but in this case it depends where the CV is to be used - the UK, the USA or even Canada or somewhere else.

But these keywords might give you something to search for in the right variety of English!

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Note added at 1 hr (2008-10-29 20:58:24 GMT)
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Sorry, I´m not sure the link works.
Førestereservelæge is given as senior registrar or senior resident af ´Fagordbogen´.

This is the entry I referred to:

(Engl.)
house officer
[residential post where the doctors work shifts which cover the whole 24 hours. Their duties will include a lot of paper work, such as writing letters to general practitioners, writing up case notes, discharge notes, death certificates and so on. If they are ‘house surgeons’, they will assist at operations]

(Engl.)
house physician
[a house physician receives specialty training at a hospital and cares for the patients under the direction and responsibility of the attending staff]

(USA)
1st year resident
[a 1st year resident receives specialty training at a hospital and cares for the patients under the direction and responsibility of the attending staff]

(Engl.)
registrar (Registrars are adressed as Doctor or Mr X, Miss or Mrs Y according to whether they are medical or surgical)
[a registrar is a senior house officer. The registrar will practically always have a higher qualification than house officers. A ‘surgical registrar’ will do the routine surgery for example, appendicectomy, hernia etc, without the supervision of a more senior surgeon but he will only perform major operations with a more senior surgeon present]

(US)
resident (Residents are termed ‘fellows’ in Canada during their first two years, ‘residents’ during their last two years. In Australia residents are called ‘interns’ or ‘junior resident medical officers’ during their first year or, alternatively, ‘senior resident medical officers’ or ‘registrars’)
[a house officer attached to a hospital for clinical training; formerly, one who actually resided in the hospital]