Near the second portion of the duodenum in the mobilization of the right colon, the fascial configuration obtained when the dissection between the right fusion fascia of Toldt and the deep subperitoneal fascia is performed,

Following the dissection between the left fusion fascia of Toldt and the deep subperitoneal fascia, a few sheets of fascia appear to the left fusion fascia of Toldt. Particularly after fascial dissection using the lateral approach, a sheet of fascia remains visible in the operative field. This is not comprehensible. Only after the complete division of the sheet is achieved can the optimal layer be ensured.

A transparent fascia is present on the dorsal side of the Denonvilliers’ fascia.

In the Kraske parasacral approach, there is a fascia on the dorsal side of the rectum of the caudal side of the rectosacral ligament.

It is understandable that many of the fasciae exist in the second portion of the duodenum when the mobilization of the right colon is performed using the medial-retroperitoneal approach (Fig. 9.2).

When observing the fascial composition in cases in which the mobilization of the sigmoid colon is complex, it is sufficient to focus one’s attention only on the deep subperitoneal fascia as an indicator (Fig. 9.3). As interpreted, the fascial structure that presents at the start of the medial-retroperitoneal procedure in right colectomy (see the Chap. 6; Fig. 6.​6) is considered to be the same as that in the sigmoidectomy procedure. That is, the traction to the ventral side of the sigmoid mesocolon would create a new fascia (Fig. 9.4).

The Denonvilliers’ fascia is often described in fusion theory due to the fact that two fasciae of the peritoneum have been fused [2–7]. Therefore, an additional fascia present on the dorsal side of the Denonvilliers’ fascia is of course the fascia involving the rectum (Fig. 9.5) because the deep subperitoneal fascia continues towards the subserosal region of the rectum (Fig. 9.1). However, the continuity of this fascia to the dorsal and cranial side is currently unresolved.