Hirschsprung's disease occurs when intramural nerves in the rectum and colon fail to migrate distally, with the intestinal distention proximal to the level at which nerve migration has stopped. Hirschsprung's Disease may be classified by the anatomic location of the aganglionic segment.


Normally the rectum lacks ganglion cells just above the pectinate line. This zone is variable in size but usually is about 2 cm in length. In patients with ultrashort Hirschsprung's disease aganglionosis involving rectum less than 2 cm from the pectinate line is associated with chronic constipation.


Typical forms:

(1) short segment (67-82% of patients)

(1a) rectum

(1b) rectum and sigmoid colon

(2) colonic segment: rectum, sigmoid colon and descending colon

(3) long segment (15-25%)

(3a) rectum, sigmoid colon, descending colon and transverse colon

(3b) rectum, sigmoid colon, descending colon, transverse colon, ascending colon

(3c) rectum, sigmoid colon, descending colon, transverse colon, ascending colon, cecum



(1) total colonic aganglionosis (3-8%): entire colon plus distal terminal ileum

(2) ultrashort (rare): involves the distal rectum below the pelvic floor. These patients often present as adults with a history of chronic constipation. The aganglionic segment is at or within 2 cm of the pectinate line, so is in the region where aganglionosis is normally expected.

(3) entire bowel (rare)


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