AJR:194, March 2010
Nan Chen, Peng Qiu Min, Zai Yi Liu, Bing Wu, Kai Qing Yang, Chun Yan Lu
OBJECTIVE. The objective of our study was to clarify the anatomic and radiologic fea¬tures of the extraperitoneal fasciae and fascial spaces associated with the rectum.
MATERIALS AND METHODS. Fourteen embalmed cadavers were studied: two for gross anatomy; six for sectional anatomy, of which two underwent histologic study; and six for space perfusion study. These examinations were followed by CT and cross dissection to observe the pelvic extraperitoneal fasciae and the role of the fasciae in the anatomic subdivi¬sion and communication of the fascial spaces. Eighty healthy subjects underwent CT or MRI to identify the imaging characteristics of the pelvic fasciae.
RESULTS. Cadaver dissection and histologic study revealed a distinct sheath consisting of dense connective tissue encasing the rectum and surrounding adipose tissue like a sleeve that divided the rectal extraperitoneal space into the perirectal space and pararectal space. Perfusion studies showed communication between the pararectal spaces and the vesical ex¬traperitoneal space anteriorly and the anterior pararenal space superiorly, but not with the perirectal space. In healthy subjects, both CT (95.0%) and MRI (97.5%) showed a circular or linear structure representing the rectal fascia outside the rectum encasing the rectum and its surrounding adipose tissue.
CONCLUSION. The extraperitoneal segment of the rectum and its surrounding adi¬pose tissue are encased by a fascia, like a sleeve, that can be seen on CT and MRI in healthy populations. The fascia divides the rectal extraperitoneal space into the perirectal space and pararectal space, and it may prevent lesions of the rectum from spreading to other pelvic ex¬traperitoneal spaces.