An investigation of human jejunal and ileal arteries.

The arrangement of jejunal and ileal arteries varies along the length of the small bowel, but the reasons for this and the functional implications are uncertain. The aims of this anatomical and histological study were to investigate quantitative differences between jejunal and ileal arteries and to investigate their relative muscularity. Ten cadaver small bowels (five males, mean age 78 years) were analysed. In each specimen, the mesentery of two standardised 40-cm lengths of jejunum and ileum were dissected and measured. Representative arterial samples from a jejunal and ileal parent artery, first arcade artery and arteriae recta were examined histologically and their relative muscularity (proportion of arterial cross sectional area occupied by tunica media) compared. No consistent differences were found between jejunal and ileal parent artery lengths, but jejunal arteries tended to be larger (mean diameter 2.2 +/- 0.2 mm vs. 2.0 +/- 0.4 mm, p = 0.08). Compared to the jejunum, the number of arterial arcades was significantly greater in the ileum (p < 0.0001), and the arteriae recta were more numerous (p = 0.02), shorter (p = 0.007) and narrower (p = 0.004). There was no statistically significant difference between the muscularity of proximal jejunal versus distal ileal arteries or between parent, first arcade and arteriae recta within the proximal jejunum and distal ileum. These quantitative data clarify conflicting statements about jejunal and ileal arterial anatomy. However, the different arterial pattern in the jejunum and ileum does not appear to be associated with differences in the muscularity of these arteries.