THE PELVIC COMPASS:
Learn, Visualise, Operate
Key Anatomical Aspects
1. Pararectal Space (White outlined area)
This is a retroperitoneal avascular space created by blunt and sharp dissection.
It lies:
Medial boundary: Rectum
Lateral boundary: Internal iliac vessels
Anterior boundary: Cardinal ligament / uterine artery
Posterior boundary: Sacrum and presacral fascia
I am demonstrating the Okabayashi pararectal space.
This space is critical for:
Safe ureterolysis
Nerve-sparing procedures
Deep infiltrating endometriosis excision
2. Denonvilliers’ Fascia (Blue marked region)
A dense fibromuscular fascial layer between:
Anterior: Posterior vaginal wall / cervix
Posterior: Rectum
It forms part of the rectovaginal septum.
Surgical relevance:
Acts as a natural plane for rectovaginal dissection
Preserving this layer reduces risk of rectal injury
It appears as the whitish, glistening fibrous plane being exposed.
3. Ureter (Right tubular structure)
The ureter is seen coursing in the retroperitoneum:
Running medial to the internal iliac vessels
Passing beneath the uterine artery.
It appears as a smooth, pale tubular structure, often with peristaltic movement.
Surgical importance:
Identification is essential before any lateral or deep pelvic dissection
Prevents ureteric injury during ligation of uterine vessels
4. Uterine Artery
Seen crossing above the ureter in the lateral pelvic wall.
Origin:
Branch of internal iliac artery (anterior division)
Course:
Travels medially within the cardinal ligament
Crosses over the ureter
In this field, it appears as a vascular structure running obliquely, often pulsatile in live surgery.
5. Retroperitoneal Structures
This dissection exposes the classic layered anatomy:
Loose areolar tissue (facilitating space development)
Pelvic autonomic nerves (hypogastric nerve and inferior hypogastric plexus)
Vascular structures (internal iliac branches)
Fascial planes separating compartments
Surgical Perspective
The dissection reflects correct anatomical plane identification, staying:
Medial to ureter
Lateral to rectum
The clean exposure of Denonvilliers’ fascia indicates precise rectovaginal plane development
This approach is fundamental in:
Deep infiltrating endometriosis surgery
Radical hysterectomy
Nerve-sparing pelvic procedures
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