肛周坏死性筋膜炎（PNF）是一种特殊类型的感染，一般由多种细菌（包括厌氧菌和需氧菌）混合感染而发病。PNF感染可沿着肛周、会阴的浅筋膜扩散，上至腹壁，下达下肢，同时感染还可能向深部蔓延，到达肛提肌上间隙、膀胱周围间隙、直肠后间隙等盆腔腹膜外间隙，甚至进一步蔓延至腹膜后间隙。这些感染常常是沿着筋膜、筋膜间隙进行播散，同时还可以沿着血管神经穿行孔进行蔓延。尽管目前医疗水平有了极大的提升和发展，但临床医生在PNF的诊断及治疗方面仍然面临巨大的挑战。本研究旨在通过大体解剖资料、病例资料、既往文献回顾性分析肛周会阴、盆腔、腹膜后筋膜及间隙解剖知识，以及PNF的感染蔓延播散途径，以期为该病的诊断及手术治疗提供参考。

Perianal necrotizing fasciitis (PNF) is a special type of infection that typically involves mixing infection with a variety of bacteria, including anaerobic and aerobic bacteria. PNF infection can spread along the superficial fascia of the perianal and perineum, up to the abdominal wall and down to the lower extremities. Meanwhile, the infection may also spread deep to the pelvic extraperitoneal space such as the superior levator anal space, the peribladder space, the retrorectal space, and even further spread to the retroperitoneal space. These infections often spread along the fascia, the fascial space, and can also spread along the vascular and nerve crossing foramen. Although the current medical level has been greatly improved and developed, clinicians still face great challenges in the diagnosis and treatment of perianal necrotizing fasciitis. The purpose of this study was to retrospectively analyze the anatomical knowledge of perianal perineum, pelvic cavity, retroperitoneal fascia and space, as well as the infection spread and dissemination route of PNF through gross anatomical data, case data and previous literature, in order to provide reference for the diagnosis and surgical treatment of PNF.