[Illustration: FIG. 24.--Acute Bed-Sores over Right Buttock.]
_Clinical Features._--Two clinical varieties are met with--the acute
and the chronic bed-sore.
The _acute_ bed-sore usually occurs over the sacrum or buttock. It
develops rapidly after spinal injuries and in the course of certain
brain diseases. The part affected becomes red and congested, while the
surrounding parts are oedematous and swollen, blisters form, and the skin
loses its vitality (Fig. 24).