The Virtual Pig Head

Why the Virtual Pig?

     The digital world is taking over medical imaging technologies. It has become the norm to use noninvasive techniques to gain digital outputs with which to understand disease or injury states prior to surgery.  These digital data sets can likewise be used by the research community in constructing virtual models for study without damage to the specimen.   

      A. Visible Human Project. – The Visible Human Project was released to the public in 1994 as the Visible Human Male and followed by the Visible Human Female in 1995. These data sets were compiled through computed tomography (CT), magnetic resonance imaging (MRI), and cryosectioning of cadavers (Web resource [WR] 1).  The project has been used to generate three-dimensional (3D) models for anatomical texts (WR 2, 3, 4) and for a variety of analyses that researchers could not perform on live subjects including virtual surgery, a technique that allows a doctor to develop surgical procedures prior to surgery or to investigate problematic conditions that will require attention during the actual surgery (WR 4).  Success of the Visible Human Project has stimulated the generation of similar 3D data sets with other animals for comparable uses. These include the lab mouse and the macaque and have been used to generate the µMRI Atlas of Mouse Development at Caltech (WR 5, 6, 7, 8; Bard et al., 1998; Dhenain et al., 2001; Sharpe et al., 2003) and the Stereotaxic MRI Brain Atlas of the Monkey (WR 9, 10). 

B. The pig. – The pig has great use in the biomedical community where it is often used as an animal model for several human disease states and developmental problems.  A listing of over 2200 types of biomedical research done on swine in the decade of 1990-2000 was assembled by the USDA Animal Welfare Information Center (WR 11). Some of the diseases include temporomandibular joint (TMJ) dysfunctions (Herring et al., 2002), mastoid air cell infections (Pracy et al., 1998), and degeneration of the knee joint (Donahue et al., 2002).   There are many reasons for using pigs as animal models, including similarity to humans in some of its anatomical structures, diet, weight, as well as some advantageous differences such as a comparatively short reproductive cycle.  The pig is also one of the prime species for xenotransplantation as treatments have been developed against pig antigens (Lam, 2004).

     C. Project achievements. – The Virtual Pig project provides a wide array of features to the scientific and educational community. Three-dimensional analysis allows views of muscle, bone, fat, and other tissues from planes that could not easily be achieved through dissection, providing important information to the many fields of study that use this species. Unlike dissection, the products of this study give the ability to look at structures without destroying their more superficial counterparts and to reanalyze their interactions, giving a greater access to these internal features. These techniques have been previously used on other animals (WR 5, 6, 7, 8, 9, 10) and add useful information to the breadth of knowledge available for the pig. It is not a goal of this study to redescribe the cephalic anatomy of the pig because this has been done in the traditional veterinary literature (Nickel et al., 1973) and on the internet (WR 12). This website is in place to complement the Visible Human Project. The website is designed to add accessibility to this data set for research and educational purposes.