 |
|
|
|
|
 |
|
Updated: 12/26/06 03:13 PM
|
|
|
|
 |
|
|
| HOME |
HEAL |
EDUCATE |
RESEARCH |
DIRECTORY |
OUTREACH |
|
Anal canal drains to inguinal nodes
|
|
The walls of the colon are endowed with dense networks of lymph capillaries and lymphoid follicles. Lymphatic drainage follows the blood vessels via two main routes - the superior and inferior mesenteric. Those proximal to the splenic flexure end in the superior mesenteric nodes and those distal in the inferior mesenteric nodes. The rectum and anal canal drain not only to the inferior mesenteric nodes but also to the iliac and sacral nodes within the pelvis. Below the pectinate line the anal canal drains to the superficial inguinal nodes which may be involved in squamous carcinoma of the anus.
|
|
Mid- and hind-gut innervation
|
|
The parasympathetic and sympathetic nerves supply the entire large intestine except for the striated muscle of the external sphincter. The nerves follow their embryological derivation. Thus, the right half of the colon has midgut parasympathetic innervation via the vagus and sympathetic fibers of the celiac plexus. Afferent sympathetic fibers from the right colon wall respond to stretch and spasm. The left half of the colon has hindgut innervation with parasympathetic fibers via the nervi erigens and sympathetics via the inferior mesenteric plexus. Pain from the right half of the colon tends to be felt in the periumbilical area and pain from the left half of the colon in the hypogastrium (lower half of the abdomen on both sides). Pain in the ileocecal area can be felt in the epigastrium or supraumbilically. In some colonic diseases pain is of somatic origin because parietal peritoneum is inflamed, or because the abdominal muscles are reflexly contracted in protective spasm. There is variability in the severity of pain of peritoneal origin: That from the upper abdomen and subdiaphragmatic area is severe while that from the deeper pelvic or posterior parietal peritoneum is less severe.
|
Next Section (G): Function »
|
|
| © Copyright University of Washington Division of Gastroenterology 1999-2008
|
