Partial and Complete Prolapse of the Rectum-Cancer of the Rectum-Rectal Injuries-Pelvic Appendix

Partial and Complete Prolapse of the Rectum

Partial and complete prolapses of the rectum through the anus are relatively common clinical conditions. In partial prolapse, the rectal mucous membrane and submucous coat protrude for a short distance outside the anus. In complete prolapse, the whole thickness of the rectal wall protrudes through the anus. In both conditions, many causative factors may be involved. However, damage to the levatores ani muscles as the result of childbirth and poor muscle tone in the aged are important contributing factors. A complete rectal prolapse may be regarded as a sliding hernia through the pelvic diaphragm.

 

Cancer of the Rectum

Cancer of the rectum is a common clinical finding that remains localized to the rectal wall for a considerable time. At first, it tends to spread locally in the lymphatics around the circumference of the bowel. Later, it spreads upward and laterally along the lymph vessels, following the superior rectal and middle rectal arteries. Venous spread occurs late, and because the superior rectal vein is a tributary of the portal vein, the liver is a common site for secondary deposits.

Once the malignant tumor has extended beyond the confines of the rectal wall, knowledge of the anatomic relations of the rectum will enable a physician to assess the structures and organs likely to be involved. In both sexes, a posterior penetration involves the sacral plexus and can cause severe intractable pain down the leg in the distribution of the sciatic nerve. A lateral penetration may involve the ureter. An anterior penetration in the male may involve the prostate, seminal vesicles, or bladder; in the female, the vagina and uterus may be invaded. It is clear from the anatomic features of the rectum and its lymph drainage that a wide resection of the rectum with its lymphatic field offers the best chance of cure. When the tumor has spread to contiguous organs and is of a low grade of malignancy, some form of pelvic evisceration may be justifiable. It is most important for a medical student to remember that the interior of the lower part of the rectum can be examined by a gloved index finger introduced through the anal canal. The anal canal is about 1.5 in. (4 cm) long so that the pulp of the index finger can easily feel the mucous membrane lining the lower end of the rectum. Most cancers of the rectum can be diagnosed by this means. This examination can be extended in both sexes by placing the other hand on the lower part of the anterior abdominal wall. With the bladder empty, the anterior rectal wall can be examined bimanually. In the female, the placing of one finger in the vagina and another in the rectum may enable the physician to make a thorough examination of the lower part of the anterior rectal wall.

Rectal Injuries

The management of penetrating rectal injuries will be determined by the site of penetration relative to the peritoneal covering. The upper third of the rectum is covered on the anterior and lateral surfaces by peritoneum, the middle third is covered only on its anterior surface, and the lower third is devoid of a peritoneal covering. The treatment of penetration of the intraperitoneal portion of the rectum is identical to that of the colon, because the peritoneal cavity has been violated. In the case of penetration of the extraperitoneal portion, the rectum is treated by diverting the feces through a temporary abdominal colostomy, administering antibiotics, and repairing and draining the tissue in front of the sacrum.

Pelvic Appendix

If an inflamed appendix is hanging down into the pelvis, abdominal tenderness in the right iliac region may not be felt, but deep tenderness may be experienced above the symphysis pubis. Rectal examination (or vaginal examination in the female) may reveal tenderness of the peritoneum in the pelvis on the right side. If such an inflamed appendix perforates, a localized pelvic peritonitis may result.