Department of Anatomical Dissection and Donation, Medical University of Lodz, Poland.
Polish Mother's Memorial Hospital Research Institute, Lodz, Poland.
Folia Morphol (Warsz). 2021;80(4):827-838. doi: 10.5603/FM.a2020.0115. Epub 2020 Sep 23.
The inferior mesenteric artery (IMA) is the third main branch of the abdominal aorta and arises at the level of L3, supplying the large intestine from the distal transverse colon to the upper part of the anal canal. The aim of this study was to characterise the course and morphology of the terminal branches of the IMA, and also creating a new IMA classification, which seems to be necessary for clinicians performing surgery in this area.
The anatomical variations in the branching patterns of the IMA were examined in 40 cadavers fixed in a 10% formalin solution. Morphometric measurements were then obtained twice by two researchers.
Due to the proposed classification system, type I characterised by a common trunk preceding bifurcation into sigmoidal branches and the superior rectal artery after giving left colic artery (LCA) occurred in 57.5% of cases, type II, trifurcation type, in 25%, type III with the superior rectal arteries originating firstly from the IMA in 5%, type IV with the ascending lumbar artery in 10% of cases and type V, a novelty, in 2.5%. The origin of IMA was observed at the level of L2/L3 in 22.5% of cases, at L3 in 25% of cases, at L3/L4 in 15% of cases, at L4 in 35% of cases and at the level of L5 in 2.5% of cases. More than one third (38.1%) of total cases with additional arteries and rapidly bifurcating branches occurred in types III, IV, and V. In women, only the IMA and LCA were significantly narrower than in men. Only the diameter of the IMA correlated with the diameter of the superior rectal artery.
The IMA is characterised by high morphological variability. The introduction of a new, structured, anatomical classification seems necessary for all clinicians.
肠系膜下动脉（IMA）是腹主动脉的第三大主要分支，起自 L3 水平，供应从横结肠远端到肛管上段的大肠。本研究旨在描述 IMA 终末分支的走行和形态，并创建一种新的 IMA 分类，这似乎对在该区域进行手术的临床医生很有必要。
在 40 具固定在 10%福尔马林溶液中的尸体中，检查了 IMA 分支模式的解剖变异。然后由两名研究人员进行了两次形态测量。
由于提出的分类系统，以 LCA 之前的共同干为特征的 I 型（I 型）在 57.5%的病例中表现为乙状结肠分支和直肠上动脉，II 型（II 型）为三叉型，占 25%，III 型（III 型）首先从 IMA 起源的直肠上动脉占 5%，IV 型（IV 型）有升主动脉占 10%，V 型（V 型）为新出现的一种，占 2.5%。IMA 的起源在 22.5%的病例中位于 L2/L3 水平，在 25%的病例中位于 L3 水平，在 15%的病例中位于 L3/L4 水平，在 35%的病例中位于 L4 水平，在 2.5%的病例中位于 L5 水平。III、IV 和 V 型中超过三分之一（38.1%）的总病例有额外的动脉和快速分支。在女性中，IMA 和 LCA 的直径明显小于男性。只有 IMA 的直径与直肠上动脉的直径相关。
IMA 具有高度的形态变异性。引入一种新的、结构化的解剖分类似乎对所有临床医生都是必要的。
