Definitions of mesorectal surgery

Mesocolic - intact mesorectum with only minor irregularities of a smooth mesorectal surface.  No defect is deeper than 5mm. No coning on the specimen. Smooth circumferential margin  on slicing

Intramesocolic - Moderate bulk to mesorectum but irregularity of the mesorectal surface. Moderate coning of the specimen towards the distal margin. At no site is the muscularis propria visible (excluding sphincter area). Moderate irregularity of the circumferential resection margin.

Muscularis propria - Little bulk to the mesorectum with defects down onto the muscularis propria and/or very irregular circumferential resection margin.

Muscularis propria dissection

Poor mesorectal dissection down onto muscularis propria

Anterior intramesorectal dissection

Anterior surface irregular intramesorectal dissection

Mesorectal plane

 Beautiful mesorectal excision showing the shiny fascia

Mesorectal plane dissection

 Mesorectal excision showing shiny mesorectal surface