Male urethral injury during rectal cancer surgery is rare but significant. Scant information is available about the distances between the rectourethral space and neighboring structures. The aim of this study is to describe the anatomical relations of the male urethra. This three-pronged study included cadaveric dissection, retrospective MRI analysis, and clinical cases. Measurements included the R-Mu distance (shortest distance between the rectum and the membranous urethra), R-Am distance (distance from the anterior rectal wall to anal margin nearest to the membranous urethra), and the anal canal–rectum axis angle. The clinical study analyzed the incidence of urethral injury and associated factors among 244 consecutive men from January 2016 to January 2023. The overall incidence of urethral injury in our series was low (0.73%), but in men with tumors < 10 cm from the anal margin, it was 4% in abdominoperineal resection and 3.2% in TaTME. On preoperative MRI, the median R-Mu distance was 1 cm (IQR, range, 0.2–2.3), the median R-Am distance was 4.3 cm (range, 2–7.3), and the median anorectal angle was 128° (range, 87–160). In the cadaveric study (nine adult male pelvises), the mean R-Mu distance was 1.18 cm (range 0.8–2), and the mean R-Am distance was 2.64 cm (range 2.1–3). Avoiding urethral injury is crucial. The critical point for injury lies 2–7.3 cm from the anal margin, with a 0.2–2.3 cm distance between the rectum and the membranous urethra. Collaborating with anatomists and radiologists improves surgeons’ anatomy knowledge.
直肠癌手术中男性尿道损伤虽属罕见，但具有重要意义。目前关于直肠尿道间隙与邻近结构间距的解剖学数据较为匮乏。本研究旨在系统描述男性尿道的解剖学关系。这项三阶段研究涵盖尸体解剖、回顾性MRI分析及临床病例分析。测量指标包括R-Mu距离（直肠与膜部尿道的最短间距）、R-Am距离（直肠前壁至最接近膜部尿道的肛缘距离）以及肛管-直肠轴角度。临床研究分析了2016年1月至2023年1月连续收治的244例男性患者中尿道损伤发生率及相关因素。本系列总体尿道损伤发生率较低（0.73%），但在肿瘤距肛缘<10cm的患者中，腹会阴联合切除术的损伤率为4%，经肛全直肠系膜切除术为3.2%。术前MRI显示：R-Mu距离中位数为1cm（四分位距0.2-2.3），R-Am距离中位数为4.3cm（范围2-7.3），肛直肠角中位数为128°（范围87-160）。尸体解剖研究（9具成年男性骨盆）显示：平均R-Mu距离为1.18cm（范围0.8-2），平均R-Am距离为2.64cm（范围2.1-3）。避免尿道损伤至关重要，损伤关键区域位于肛缘上方2-7.3cm范围内，此区域直肠与膜部尿道间距为0.2-2.3cm。与解剖学家和放射科医师的协作有助于提升外科医生的解剖学认知。
肿瘤(癌症)患者之家