Inferior mesenteric artery: detailed anatomy and morphometry

The inferior mesenteric artery (IMA) supplies blood to the distal transverse colon, descending colon, sigmoid colon, and rectum. A thorough understanding of IMA anatomy is crucial in colon cancer surgery and emerging percutaneous interventions. However, there has been only limited research on its precise morphometry, including vessel length, diameters, and branching angles. The aim of this study was to provide a detailed analysis of the IMA, focusing on parameters essential for optimising percutaneous vascular treatments and colon surgery.

Multiplanar reconstructions and maximum intensity projections were generated from contrast-enhanced computed tomography angiography scans of 105 human bodies obtained during forensic examinations. The inferior mesenteric artery and its branches were assessed, with each scan analyzed and measured using specialized software. Left colic artery (LCA) was divided into two groups based on its trunk length, and superior rectal artery (SRA) was divided into three groups.

A short trunk of the LCA was observed in 38.1% of cases, with an average length of 2.4 mm. A long trunk was observed in 61.9% of scans, with an average length of 42.6 mm. SRA type 1 was found in 53.3% of cases, type 2 in 38.1% of cases, and type 3 in 8.6% of cases. A greater number of sigmoid arteries was observed in women than in men (p = 0.001).

In patients with a short left colic artery trunk, procedures in its branches may be easier due to wider angles and larger diameters, improving catheter access. Additionally, extra superior rectal arteries may form before the sigmoid arteries, which could impact upon colon surgery.