http://en.wikipedia.org/wiki/Sexual_fetishism - top paragraph:
"Body parts may also be the subject of sexual fetishes (also known as partialism) in which the body part preferred by the fetishist takes a sexual precedence over the owner."
Then the limited entry at -
http://en.wikipedia.org/wiki/Partialism
"Partialism refers to a sexual interest with an exclusive focus of a specific part of the body.[1] Partialism is categorized as a paraphilia in the DSM-IV-TR of the American Psychiatric Association.[2] Individuals with partialism sometimes describe the anatomy of interest to them as having equal or greater erotic attraction for them as do the genitals.[3]
Partialism, such as for the foot, occurs both in heterosexual and homosexual individuals.[4][5]"
Partialism was taught to me as being a paraphilla group that falls under 'fetish' and they appear to agree. So, you can indeed have a clinical foot fetish and in fact, feet were the body part most often referred to in relation to partialism in my research. However, the whole area is very fluid and 'they' move things around in classification all the time. After all, homosexuality was on the list of clinical paraphillias until rather recently but now isn't.