Colorectum

Abstract

The colon and rectum together measure between 125 and 140 cm in the adult. The colon is divided into the caecum (10 cm), ascending (15 cm), transverse (40 cm), descending (25 cm) and sigmoid (25–40 cm) colons. The rectum measures approximately 13–15cm (Figure 5.1). The main function of the colon is absorption of water and electrolytes and the storage of faecal material until it can be excreted. The caecum is that part that lies below the ileocaecal valve and receives the opening of the appendix. It is completely surrounded by peritoneum allowing it to be mobile in the right iliac fossa. The base of the appendix is attached to the posteromedial surface of the caecum. The ascending colon extends upwards from the caecum to the inferior surface of the right lobe of liver.