The corpus cavernosum recti

Summary

The structure of the hemorrhoidal plexus is really that of a corpus cavernosum and it fulfills an important role normally in maintaining anal continence. It is situated asymmetrically in the inner portion of the anal canal because the rectum passes from left to right after leaving the abdomen to enter the pelvis and reach the pelvic floor.

The “functional unit” of the corpus cavernosum recti is a narrow, partly tortuous, thick-walled artery which terminates, without interposed capillaries, directly into the hollow spaces which are separated from each other by tough connective tissue septa. The blood remains arterial and acts as a “filler,” playing no metabolic role. For this reason, bleeding from hemorrhoids is always bright red.

The studies were made on an organ which the author reconstructed from serial sections.