Biomedical Engineering Reference
In-Depth Information
Pictures of the body's inside, including cells, are thus not self-explanatory.
A core feature of cytology, including the Pap smear, is that the visual analysis
of magnifi ed cells is guided by predetermined classifi cations and involves the
distinction between, and identifi cation of, cells in a continuum between the
normal and the pathological.
The normal, the pathological and the spectrum between
The concept of 'the normal' is used across disciplinary borders. Normality
can be defi ned in different ways for different purposes, e.g. statistical or
clinical (Posner 1993). In medicine, 'the normal' has been defi ned as agreeing
with the regular and established type (Dorland and Anderson 1993). About
four decades ago Ryle (1961) argued that the meaning of the normal, which
is often equated with healthy, is problematic in biomedicine. According to
Ryle the conceptualisation of the normal is unclear since variations of the
normal have received less interest and attention than the measurements of
disease. Birke (1999), a feminist biologist, points out that 'physiological
systems assume a “typical” or “normal” individual' (p. 27). For Birke the
notion of the pathological is the most problematic, claiming that in modern
biomedical texts deviations from the normal are consistently represented as
'pathological' rather than as 'differences'. Thus, from different angles Ryle
(1961) and Birke (1999) problematise the possibilities for variations within
the categories of the normal and the pathological, raising questions about at
which point the one is transformed into the other.
The Pap smear
The Pap smear epitomizes what has been described as the core features
of 'surveillance medicine': the problematisation of the normal and the
blurring of the binary relation between the normal and the pathological
(Armstrong 1995). As is the case with most screening tests, Pap smears
'yield continuous variables' with a gradual transition from normal to morbid
conditions (Swedish Council on Technology Assessment in Health Care
1996: 13). As mentioned, Pap smears are analysed in a continuum between
the normal and the pathological using the microscope and a cytological
classifi cation systems. Whereas the term classifi cations connote fi xed
categories, Pap smear classifi cations have been in a state of fl ux. According
to Clarke and Casper (1996), the Papanicolaou classifi cation system has
undergone 'several incarnations over time' (p. 607). In addition, a variety
of conceptualisations have been used in the literature concerning the cells
in between the normal and the pathological that are detected by means of
the Pap smear. For example, Armstrong (1995) labelled the abnormal cells
detected through screening a 'semi-pathological pre-illness at-risk state'
(p. 402). In medicine, CIN (cervical intraepithelial neoplasia) has been
described as 'a single diagnostic category' and 'a single disease continuum'
