[Verse 1]
Twelve to fifteen centimetres, rectum starts its run
From the sigmoid junction down to where the anal canal's begun
Three lateral curves inside, the valves of Houston fold
Kohlrausch's shelf sits anterior, that's the story told
Peritoneal reflection — anterior higher, posterior drops lower
Anterior eight centimetres up, posterior five, now you know the order
Below the reflection it's extraperitoneal, remember where you stand
Operative territory, every centimetre planned
[Chorus]
Mesorectum wrapped in fascia propria, that's the holy plane
Heald dissected sharp and clean, total mesorectal domain
Waldeyer's fuses sacrum back, Denonvilliers guards the front
Superior hypogastric splits to hypogastric nerves — don't blunt
Three rectal arteries, three source points feeding in
Superior from the IMA, middle and inferior begin
Dentate line divides the world, lymphatics split in two
Above drains mesorectal-iliac, below goes inguinal through
[Verse 2]
Fascia propria envelops the mesorectum like a sheath
Waldeyer's presacral fascia anchors deep beneath
Fuse at the rectosacral ligament, S4 level territory
Violate that plane and haemorrhage writes a different story
Denonvilliers anterior — condensed peritoneal fold
Separates the rectum from the prostate, seminal vessels cold
The neurovascular bundles hug the lateral pelvic wall
Injure them and erectile function answers with a fall
Superior hypogastric plexus — sympathetics from L1 to L3
Splits to hypogastric nerves, parasympathetics S2 to S4 run free
Pelvic splanchnics merge below to form the inferior plexus wide
Continence and erection both depend on what survives inside
[Verse 3]
Surgical anal canal — anorectal ring down to the groove
Anatomic canal shorter, dentate line sits in the groove
Columns of Morgagni — longitudinal folds, eight to ten
Crypts sit at their bases, glands invade the intersphincteric den
Transition zone above the dentate, squamous below the line
Columnar above, that gradient of epithelium — by design
Internal sphincter — smooth involuntary, thickened circular extension
External sphincter — skeletal, voluntary, triple-looped suspension
Puborectalis slings the anorectal angle into place
Levator ani forms the pelvic floor, the base of every case
That intersphincteric plane between them — surgical corridor
Anorectal ring is crucial — cut it and continence is no more
[Bridge]
Five spaces wrap the anal canal like chambers in a vault
Perianal sits superficial, ischioanal — wide at fault
Intersphincteric runs between the sphincters, cryptoglandular source
Supralevator communicates above, horseshoe tracks its course
Deep postanal space connects both sides behind the canal
Horseshoe abscess spreads from there — posterior midline's the interval
Lymphatics split precisely at the dentate — nature's billing code
Above it mesorectal nodes, below it inguinal road