Objective To study the concept and understand the feasibility and steps involved in performing a novel ultrasound technique called saline-infusion sonoPODography (SPG). This would be completed in patients already undergoing routine hysterosalpingo-contrast-sonography (HyCoSy)/saline-infusion sonohysterography (SIS) for intracavitary pathology or fertility purposes. The objective is to further characterize the aspects of the posterior compartment, such as the uterosacral ligaments (USLs), rectovaginal septum (RVS), bowel and pouch of Douglas (POD). Methods This was a prospective observational study from January to September 2018. All women had SPG attempted at the time of a planned HyCoSy to assess tubal patency for fertility purposes and/or SIS to assess for intracavitary pathology. Following introduction of fluid into the POD, an assessment of the posterior compartment, including the POD, rectovaginal septum (RVS), and uterosacral ligaments (USLs) was performed and visualization of these structures recorded. The infused POD fluid created an acoustic window allowing a ‘stand-off’ view of these structures. Three-dimensional (3D) volumetric acquisitions of the POD with fluid collection were recorded and volumes were calculated using Virtual Organ Computer-aided AnaLysis (VOCALTM). Results Fifty-six patients underwent SPG attempt in a systematic manner. Thirty-nine (73.2%) patients had fluid collection in the POD with a mean fluid volume of 7.11cm3. There was no difference in the POD fluid collection status stratified by various patient characteristics (e.g. uterus orientation, indication for procedure, endometriosis presence). The rate of POD fluid collection amongst women with evidence of endometriosis was 77.3% vs. without 50.0% (p = 0.08). Amongst patients with POD fluid collection, the fluid volume did not significantly differ between those with evidence of endometriosis and those without. For visualizing structures in the posterior compartment, POD fluid collection provided more clear sonographic views of difficult to visualize anatomical structures including the RVS, USLs, torus uterinus, and the bowel. More importantly, we propose that when SPG-introduced fluid collection was present in the POD, normal USLs and the true POD could be visualized. We also propose that POD fluid potentially allows for the identification of an abnormal POD peritoneum, which may contain superficial endometriosis. Conclusions The majority of patients had iatrogenic fluid collect in the POD during SPG. SPG allows for identification of the RVS, USLs, and POD in most patients. Creation of an iatrogenic acoustic window in the POD could be a useful technique added to routinely performed pelvic ultrasound assessments in patients presenting with infertility and/or pelvic pain.