and ventrally by the sternum. The sternum consists of segments,
the sternebrae (st.); anteriorly there is a bony manubrium (mb.),
posteriorly a thin cartilaginous plate, the xiphisternum (xi.). Seven
pairs of ribs articulate by cartilaginous ends (sternal ribs) with the
sternum directly, as indicated in the figure; five (false) ribs are joined,
to each other and to the seventh, and not to the sternum directly.
The last four ribs have no tuberculum (Section 77).