Anatomical variations in the level of origin of the sigmoid colon from the descending colon and the attachment of the sigmoid mesocolon.

The origin of the sigmoid colon is considered constant as is the V-shaped attachment of the sigmoid mesocolon attachment. This study was undertaken to establish anatomical variations in the level of origin of the sigmoid colon (590 autopsies; 403 Africans, 91 Indians, and 96 Whites), and the shape of the attachment of the sigmoid mesocolon (211 autopsies, 127 Africans, 47 Indians, and 37 Whites) in different population groups. The low-level origin was significantly less common among Africans compared with the other population groups (P = 0.003) and the high-level origin was significantly more common in Africans (P = 0.003). A midlevel origin was similar in all three groups. The shape of the mesocolon attachment was either straight (94), inverted U-shaped (79), or inverted V-shaped (38). The straight shape was more common in Whites (Whites vs. African and Indian P = 0.003), and the U-shape more common in Africans (African vs. Whites P = 0.042). The distribution of the V-shape was similar. There are anatomical variations in the level of origin of the sigmoid colon from the descending colon as well as in the shape of the attachment of its mesocolon. These variations are population based.