Organ Inversion

ORGAN INVERSION (from Latin inversio - turning inside out, eversion), a term used to denote cases where the internal surface of a hollow organ protrudes outward through an artificial or natural opening and turns inside out. Thus, one speaks of inversion of the uterus when it turns inside out and its mucous membrane becomes as if it were the outer surface of the organ; one speaks of inversion of the bladder when its wall (or mucous membrane) protrudes through the urethral opening (in women) or through a congenital defect in the anterior abdominal wall (e.g., in ectopia of the bladder); in the latter case, instead of inversion, the term extrophy (exstrophia vesicae) is also used. Sometimes the phenomena of inversion are simply referred to as prolapse, which is correct insofar as inversion is often combined with prolapse (e.g., inversio et prolapsus uteri); on the other hand, not every prolapse is simultaneously an inversion. The term inversion is also used to denote abnormal positions of certain organs, without them being turned inside out, prolapsed, or otherwise pathological (thus one speaks of situs viscerum inversus).