In the right window is a fragment of the ontology, showing anatomical entities in relation to the focus concept, which is highlighted. The fragment of the ontology shown in the right window is called the ‘concept space’, namely those entities which are only one ‘generation’ –i.e. one link— away from the focus concept.  The straight lines indicate the is-a relation; the ‘parent’ of the urethra in the is-a relation is the pelvic viscus; the other pelvic viscera, which are the siblings of urethra, are also listed.  The lines with circles at each end indicate the component structure relation; the  superstructure, one generation up, that the urethra is a component of is the pelvic urinary system; the urethra also has three component parts, the prostatic urethra, the penile urethra, and the membranous urethra. (Technically, an is-a relation also exists between the urethra and its three components, but to avoid visual complexity, the line indicating that relation is not displayed). As more concepts and relations are added to the ontology, the concept space will become more crowded; for this reason, we have decided to limit the concept space to entities one link away from the focus concept.

     To see any other concept in the concept space of the focus concept, the user  clicks on a label; that label becomes the focus concept in the ontology window and the labeled image appears in the left window (if available).  For example, if the user clicks on the prostatic urethra, its concept space appears in the right window; this space includes the urethra, the component of which the urethra is part; the concept space also  include an anatomical landmark of the prostatic urethra, namely the urethral crest, as shown in Figure 3.

     The landmark relation between the urethra and the urethral crest is indicated by the arrow.

     The ontology fragment shown was developed in conjunction with the lecture application described in [3].  However, we are in the process of developing a variety of other applications for teaching anatomy, and are collecting a variety of anatomical images, which we expect to grow quite large over time.  We are therefore also concerned about how to organize these images in a way that makes them readily available and reusable for a variety of teaching, study and research application.