The rectum is the lower part of the large intestine extending from the sigmoid colon to the anal canal. It is around 5 inches long and located in the pelvis in front of the sacrum and coccyx. It has two flexures that follow the curves of the sacrum and coccyx. The upper third is covered in peritoneum while the lower third has no peritoneal covering. It is supplied by branches of the inferior mesenteric artery and drains into internal iliac and inferior mesenteric lymph nodes. A thorough understanding of rectal anatomy is important for surgical management of rectal conditions and cancer.

1. By:
Dr. Belal Mansoor
Taiz university
2018

2. OverviewOverview
Introductions
Location of the rectum
extent of the rectum
Dimensions
Flexures
Peritoneal relations
Visceral relations
Blood supply
Lymphatic drainge
Nerve supply
Clinical aspects

3. A thorough understanding of
anatomy is integral to the
surgical management of problems
of the colon and rectum.

4. RECTUM ANATOMY
 The rectum is the lower part
of the alimentary tract
extending from the sigmoid
colon to the anal canal.
 Location :
 In front of lower three
pieces of sacrum and the
coccyx.

5. Rectum
 It is about 5 inches long (12–15 cm).
 After surgical mobilization, the
rectum can be stretched to 15–20 cm
in length.

6. There is some
controversy about the
definition of the
proximal and distal
extent of the rectum.

7. THE RECTUM
begins:
 Most surgeons consider the
rectosigmoid junction to be at
the level of the sacral
promontory.
 Surgeons have traditionally
placed the upper border of the
rectum at the peritoneal
reflection.
 Anatomists consider the
rectosigmoid junction to be
located at the level of S3.
S3
rectum

8. THE RECTUM
begins:
Others consider the
rectosigmoid
junction to be
the narrowest
portion of the
large intestine
where the teniae
fuse together to
form a single
anterior tenia.
( where the taeniae
completely
merge).

9. The Rectum
The rectum Structurally
has:
NO taeniae coli,
NO omental appendices,
NO sacculations (haustra of
the colon)..

10. At the rectosigmoid junction, the
three taeniae coli become broad and
fuse together, and the rectum is
totally invested with two complete
muscle layers.
This explains why diverticula do not
form in the rectum.

11. RECTUM
 The rectum Ends
at the anorectal
junction (the point
where passing
through the levator
ani muscles):
 2-3 cm in front
of and a little
below the
coccyx
 at the level of the
anorectal ring
(the level of the
puborectalis sling)
.

12. The anorectal junction
The rectum piercing the
pelvic diaphragm and
becoming continuous with
the anal canal.

14. RECTUM
 Its caliber is
similar to that of
the sigmoid colon (
~ 4cm) at its
commencement,
but it is dilated
near its
termination,
forming the rectal
ampulla.

15. The rectal ampulla
 The rectal ampulla (or ampulla recti)
is the dilated section of the rectum
where feces are stored until they are
eliminated via the anal canal.

18. Rectal Flexures (Shape(
 The rectum is curved
Antero-posteriorly and
laterally:
A. Antero-posterior
flexures :(2 flexures ):
1. Sacral flexure
 Follows the curve of
the sacrum and coccyx
1. Perineal flexure /
Anorectal flexure
 In the terminal part of
the rectum

19. the lateral flexures must be remembered when one is passing
a sigmoidoscope to avoid causing the patient unnecessary
discomfort.
Upper
flexure
Middle
flexure
Lower flexure
B.Lateral Flexures : 3 flexures
Upper flexure: with convexity to the right.
Middle flexure :Is the most prominent one with convexity to the
left.
Lower flexure : with convexity to the RT.

20.  The middle rectal fold
corresponds to the level
of the anterior peritoneal
reflection
 The folds are
encountered by the
sigmoidoscope at
• 5–6,
• 8–9,
• and 11–13 cm
from the anal verge.

21. anterior peritoneal reflection
 The peritoneal reflection is 7
to 9 cm from the anal verge
in men and 5 to 7.5 cm in
women.
 This anterior peritonealized
space is called the pouch of
Douglas, pelvic cul-de-sac,
or rectouterine pouch and
may serve as the site of so-
called drop metastases from
visceral tumors.

22.  peritoneal
metastases can
form a mass in the
cul-de-sac (called
Blumer’s shelf )
that can be
detected by a
digital rectal
examination.

23. VALVES OF HOUSTON (transverse folds(
They are lost after full surgical mobilization of the rectum, a maneuver that may
provide approximately 5 cm of additional length to the rectum, greatly facilitating
the surgeon’s ability to fashion an anastomosis deep in the pelvis.

24. VALVES OF HOUSTON
 It is thought that these folds serve
to support the weight of the feces
and to prevent excessive distention
of the rectal ampulla.

26. PERITONEAL COVERING
The rectum is a retroperitoneal structure.
 the upper third :
 completely covered by
peritoneum except for a
small segment posteriorly
where the superior
hemorrhoidal vessels descend
through the mesorectum to
supply the rectum.
 the middle part :
 front ( ventrally) .
 The lower third :
 no peritoneal covering .
the rectum

27. PERITONEAL COVERING
 the posterior surface of rectum
is almost completely
extraperitoneal.

28. TRAUMA Seventh Edition Kenneth L. Mattox

29. Intraperitoneal rectum Injuries
 Because of the anatomical and clinical
similarities between the
intraperitoneal rectum and the distal
left colon,
intraperitoneal rectal injuries are
managed like colon injuries, the
vast majority amendable to
primary repair.
TRAUMA Seventh Edition Kenneth L. Mattox

30. extraperitoneal rectum Injuries
 The lower third of the rectum is
completely extraperitoneal and makes
exposure and repair of any injuries
difficult.
 the cornerstone of extraperitoneal rectal
injuries was based on a triad consisting
of :
 fecal diversion,
 presacral drainage,
 and distal rectal washout.
TRAUMA Seventh Edition Kenneth L. Mattox

31. FASCIA AROUND THE RECTUM
 Fascia of DENOVILLIER
 Fascia of WALDEYER

32. Fascia of DENOVILLIER
 Fascia of
DENONVILLIER-
anterior to the
rectum
(rectoprostatic
fascia) in male.
 In female
Denonvilliers
fascia being often
scant and difficult
to identify.

33. WALDEYERS FASCIA
•The presacral
fascia lines
the anterior
aspect of the
sacrum,
enclosing the
sacral vessels
and nerves.

34. .
 The lymphatics are contained within the
mesorectum, and total mesorectal
excision adheres to the basic surgical
oncologic principle of removal of the cancer in
continuity with its blood and lymphatic
supplies.
 Resection of the rectum by this technique, and
based on a thorough understanding of
anatomy, has been shown to reduce markedly
the incidence of subsequent local recurrence of
rectal cancer.

35. Mesorectum
 Mesorectum: The
mesentery of the
rectum, i.e.,
mesorectum, is the
perirectal fatty
lymphovascular
tissue extending the
length of the rectum.
 The mesorectum
encases the rectum
as a thick cushion
mainly posteriorly
and laterally.

36. FASCIA AROUND THE RECTUM
 The posterior aspect of the rectum is invested
with a thick, closely applied mesorectum.
 A thin layer of investing fascia (fascia propria)
coats the mesorectum and represents a distinct
layer from the presacral fascia against which it
lies.
 During proctectomy for rectal cancer,
mobilization and dissection of the rectum
proceed between the presacral fascia and
fascia propria..

37. Relations

38. Relations
Posteriorly
 3 Bones & Ligaments
 Lower ½ of the sacrum
 Coccyx
 Anococcygeal ligament
 3 Muscles
 Piriformis
 Coccygeus
 Levator ani
 3 Vessels
 Median sacral VS
 Superior rectal vs
 Lower lateral sacral vs
 3 Nerves
 Lower 3 the sacral nerves
 the sympathetic trunks
 Coccygeal nerves

39. :BLOOD SUPPLY
Arteries
 Superior rectal (hemorrhoidal)
artery :
 Middle rectal artery
 From internal iliac artery
 Distributed mainly to the
muscular coat.
 lnferior rectal artery:
 Is a branch of the internal
pudendal artery in the
perineum. It anastomoses
with the middle rectal artery
at the anorectal junction.

40. Superior rectal (hemorrhoidal) artery:
 It is Continuation of
inferior mesenteric
artery.
 It gives three branches
at3,7,'l 1 O'clock.
 Surgical importance :
Mother piles at these sites.

41. :THE RECTUM
Arteries
 The median sacral artery:
 It sends several very small branches to the
posterior wall of the rectum.
Surgical Anatomy and Technique Lee J. Skandalakis Fourth Edition

42. THE RECTUM
Venous drainage
 The veins
drainage of
the rectum
correspond
to the
arteries.

44. Venous drainage
 Remember:
 Anastomoses occur
between:
the superior rectal vein
(portal) and
the middle and inferior
rectal veins (systemic),
constituting a potential
porto-systemic
shunt.

45. Lymph Drainage
 Lymphatic vessels and lymph nodes follow
the regional arteries.
 Lymphatic channels in the upper and middle
rectum drain superiorly into the inferior
mesenteric lymph nodes.
 Lymphatic channels in the lower rectum drain
both:
 superiorly into the inferior mesenteric lymph nodes
 laterally into the internal iliac lymph nodes.

46. Lymph Drainage

47. Lymph Drainage
 Downward spread of lesions of the
rectum is rare; perhaps only 2 %
may spread downward.
Surgical Anatomy and Technique Lee J. Skandalakis Fourth Edition

48. Nerve Supply
 The nerve supply is from the
sympathetic and parasympathetic
nerves from the inferior
hypogastric plexuses.
 The rectum is sensitive only to
stretch.

51. sources
 Surgical Anatomy and Technique Lee J. Skandalakis
Fourth Edition
 TRAUMA Seventh Edition Kenneth L. Mattox
 Gray’s Anatomy for Students
 Richard S. Snell – Clinical Anatomy by Regions
 Last’s Anatomy - Regional and Applied
 Frank H. Netter – Atlas of Human Anatomy

52. THANK YOU
.