Age-related features of the colon

The large intestine of a newborn is short, its length is on average 63 cm, there are no haustra of the colon and omental appendages. The haustra appear in the 6th month, and the omental appendages - in the 2nd year of the child's life. By the end of infancy, the large intestine lengthens to 83 cm, and by 10 years it reaches 118 cm. The tapes of the colon, haustra and omental appendages are finally formed by 6-7 years.

The cecum in a newborn is not clearly delimited from the appendix, its width (1.7 cm) prevails over its length (1.5 cm). The cecum takes on a typical adult appearance by the end of the first childhood period (7 years). The cecum is located above the wing of the ilium. The intestine descends into the right iliac fossa by mid-adolescence (14 years) as the ascending colon grows.

The ileocecal opening in a newborn is annular or triangular, gaping. In children over one year old, it becomes slit-like. The ileocecal valve has the appearance of small folds. The length of the appendix of a newborn varies from 2 to 8 cm, its diameter is 0.2-0.6 cm. It communicates with the cecum through a gaping opening. The formation of the valve closing the entrance to the appendix begins with the appearance of a fold at the entrance to the appendix at the end of the first year of life. The length of the appendix during this period averages 6 cm, by the middle of the second childhood (10 years) it reaches 9 cm. The mucous membrane of the appendix of a newborn in the 1st year of life contains a large number of lymphoid nodules. The nodules reach their greatest development in childhood.

The ascending colon in a newborn is covered by the liver. By 4 months, the liver is attached only to its upper part. In adolescents and young men, the ascending colon acquires a structure characteristic of an adult. The maximum development of this part of the intestine is observed at 40-50 years.

The transverse colon of a newborn has a short mesentery (up to 2 cm). The intestine is covered by the liver in front. At the beginning of early childhood (1 1/2 years), the width of the mesentery increases to 5.0-8.5 cm, which contributes to increased intestinal mobility. In children of the first year of life, the length of the transverse colon is 26-28 cm. By the age of 10, its length increases to 35 cm. The transverse colon is longest in old people.

The descending colon in newborns is about 5 cm long. By the age of 1 year, its length doubles, at 5 years it is 15 cm, at 10 years - 16 cm. The intestine reaches its greatest length in old age.

The sigmoid colon of a newborn (length about 20 cm) is located high in the abdominal cavity, has a long mesentery. Its wide loop lies in the right half of the abdominal cavity, sometimes touching the cecum. By the age of 5, the loops of the sigmoid colon are located above the entrance to the small pelvis. By the age of 10, the length of the intestine increases to 38 cm, and its loops descend into the cavity of the small pelvis. At 40 years, the lumen of the sigmoid colon is widest. After 60-70 years, the intestine becomes atrophic due to thinning of its walls.

The rectum of a newborn is cylindrical, has no ampulla or bends, folds are not expressed, its length is 5-6 cm. During the period of early childhood, the formation of the ampulla is completed, and after 8 years - the formation of bends. The anal columns and sinuses in children are well developed. Significant growth of the rectum is observed during the period of second childhood (after 8 years). By the end of adolescence, the rectum has a length of 15-18 cm, and its diameter is 3.2-5.4 cm.

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