Rectum means straight as if ruled. This is a misnorma,for it is curved in conformity with the hollow of the sacrum. Rectum is continuous with the sigmoid colon and there is no change of structure at the junction. The distinction is a matter of peritoneal attachment; where there is a mesocolon, the gut is called sigmoid colon and where there is no mesentery, it is called rectum . Where the muscle coats are replaced by sphincters it becomes the anal canal. The rectum begins in the hollow of the sacrum at the level of its 3rd. Piece and it curves forwards over coccyx and ano-coccygeal raphe. It is 15 cm long. The 3 tinea of the sigmoid colon come together over the rectum invest it in a complete outer layer of the longitudinal muscle. The upper and lower ends of the rectum lie in the midline but the ampulla is convex to the left. Rectal valves of Houston,2 on the left and one on the Right are produced by circular muscles of the gut.

1. Dr. NDAYISABA CORNEILLE
CEO of CHG
MBChB,DCM,BCSIT,CCNA
Supported BY

2. RECTUM
• Rectum means straight as if ruled. This is a misnorma,for
it is curved in conformity with the hollow of the sacrum.
• Rectum is continuous with the sigmoid colon and there is
no change of structure at the junction. The distinction is
a matter of peritoneal attachment; where there is a
mesocolon, the gut is called sigmoid colon and where
there is no mesentery, it is called rectum . Where the
muscle coats are replaced by sphincters it becomes the
anal canal.
• The rectum begins in the hollow of the sacrum at the
level of its 3rd. Piece and it curves forwards over coccyx
and ano-coccygeal raphe.
Dr Ndayisaba Corneille 2

3. The sigmoid colon and Rectum.
Dr Ndayisaba Corneille 3

4. Cont. Rectum
• It is 15 cm long.
• The 3 tinea of the sigmoid colon come
together over the rectum invest it in a
complete outer layer of the longitudinal
muscle.
• The upper and lower ends of the rectum lie in
the midline but the ampulla is convex to the
left.
• Rectal valves of Houston,2 on the left and one
on the Right are produced by circular muscles
of the gut.
Dr Ndayisaba Corneille 4

5. RECTAL VALVES OF HAUSTON
Dr Ndayisaba Corneille 5

6. Cont.
At the sigmoid-rectal junction, the 3 tinea coli spread out to form the outer
longitudinal layer and the fatty appendices epiploicae are discontinued.
The rectum posses no mesentery, but the pelvic peritoneum of the posterior
wall of the pouch of Douglas is dapped over it in the upper part . The upper 1/3
is clad in front and on both sides, the middle 1/3 in front only and the lower 1/3
not at all by peritoneum.
The upper part of the rectum is usually empty, but the lower part ,resting on the
pelvic floor ,is distended into the ampulla and contains resting flatus and faeces.
The upper and lower part of the rectum lie in the midline, but the ampulla is
convex to the left. 3 lateral curves are produced, each being marked on the
anterior of the ampulla by horizontal shelf (RECTAL VALVES of HOUSTON).
THEY LIE 2 ON THE LEFT AND ONE ON THE RIGHT .THE Valves ARE PRODUCED BY
CIRCULAR MUSCLE OF THE GUT.
THE PURPOSE OF THE VALVES IS NOT CLEAR, BUT THEY MAY BE CONCERNED
WITH THE SEPARATION OF MUCUS FROM THE FAECES, Holding UP FAECES
WHILE ALLOWINNG FLATUS TO PASS.
Dr Ndayisaba Corneille 6

7. Blood supply to the Rectum.
• Derived principally from the artery of the hind gut, the
inferior mesenteric artery, whose superior rectal branch
,supplies the mucus membrane as far down as the
mucocutaneous junction of the anal canal (Hilton's line ). The
muscle wall of the rectum receives a reinforcement from the
middle rectal artery, a branch of the internal Iliac artery.
• The inferior rectal artery, a branch of the internal pudendal
artery, anastomoses with the middle rectal artery.
• The superior rectal artery divides into right and left branches
and the former into anterior and posterior branches.
Dr Ndayisaba Corneille 7

8. Blood supply to the Rectum and
Anal canal
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9. Cont. of blood supply to the
RECTUM
• These 3 branches sink into the muscle walls ,in
line with the 3 primary hemorrhoids( 4,7 and
11 o'clock).
• The muscles of the wall of the ampulla and
upper part of the anal canal receives branches
from the middle and inferior rectal arteries
and supply the blood to the mucus membrane
but little anastomoses with branches of the
superior rectal artery.
Dr Ndayisaba Corneille 9

10. Venous return.
• Veins correspond with arteries .
• Superior rectal vein is a tributary of the portal
circulation and drains into the inferior
mesenteric vein. The middle and inferior
rectal veins drain into the internal iliac and
internal pudendal veins respectively. The
anastomosis between the rectal veins form an
important portal systemic anastomosis.
Dr Ndayisaba Corneille 10

11. Lymphatic drainage.
• Correspond with the 3 main sources of arterial
supply.
• Lymph from the upper part of the rectum to
the inferior mesenteric lymph nodes to the
para aortic lymph nodes.
• Lymph from the lower part of the rectum
follow the middle rectal artery to the internal
iliac group of lymph nodes.
Dr Ndayisaba Corneille 11

12. Nerve supply.
• derived from both parts of the autonomic
nervous system.
• Sympathetics –from pelvic plexuses and by
fibers which accompany inferior mesenteric
and superior rectal arteries from the coeliac
plexus.
• Parasympathetic supply – from S2 ,3 or S3,4
by the nervi erigentes.
• The rectum is only sensitive to stretch.
Dr Ndayisaba Corneille 12

13. Fascia of the rectum.
• Posteriorly-a sheet of fascia , suspends the lower part
of the ampulla to the hollow of the sacrum. It encloses
the superior rectal vessels (artery, veins and
lymphatics). It is known as fascia Waldeyer.
• Laterary – the middle rectal artery and branches and
branches of the pelvic is enclosed in slight
condensation of areolar tissue – the lateral ligament of
the rectum.
• The fascia of Waldeyer, the lateral ligaments, the pelvic
peritoneum and vessels and most of all the pelvic floor
combine to hold the rectum stable and in position.
Dr Ndayisaba Corneille 13

14. Cont.
• Anteriorly, some muscle fibers leave the lower
part of the ampulla and pass forwards
towards the apex of the prostate and the
commencement of the membranous urethra.
They form the recto urethralis muscle.
Dr Ndayisaba Corneille 14

15. RECTUM AND ANAL CANAL
Dr Ndayisaba Corneille 15

16. Relations of the rectum.
• POSTERIORLY: 3 INFERIOR sacral vertebra and coccyx
and the anal coccygeal ligament. Pyriformis, levetor
ani muscles the sacral plexus and the sympathetic
trunk.
• Anteriorly : Males- upper 2/3 of the rectum is
covered by peritoneum and is related sigmoid colon
and coils of the ileum which occupy the retro vesical
pouch.
• The lower 1/3 of the rectum which is devoid of
peritoneum, is covered by the posterior surface of
the bladder, to the termination of the vas deferens
and the seminal vesicles on each side of the prostate.
Dr Ndayisaba Corneille 16

17. Female relations.
• Relations of the upper 2/3 of the rectum are
similar to those of the males.
• Lower 1/3 is related to the posterior surface of
the vagina.
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18. Relationship of the rectum in a
female.
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19. The anal canal.
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20. The anal canal.
– The junction of the rectum and the anal canal is at the
pelvic floor i.e. the level where the pubo rectalis
muscle clasps the gut and angles it forwards.
– Anal canal extends from this level to the skin of the
perineum‘. It is 1.5” long.
– The upper 2/3 is derived from the cloaca(endoderm)
the lower 1/3 from the anal pit (ectoderm)
– The junction of the 2 is at Hilton's white line. This is a
water shed dividing the upper and lower zones
arterial supply and venous and lymphatic drainage.
– In the upper (cloacal ) there is a dentate ring produced
by folds mucus membrane termed anal “valves”.
Dr Ndayisaba Corneille 20

21. JUNCTION BETWEEN THE RECTUM
AND THE ANAL CANAL .
Dr Ndayisaba Corneille 21

22. Anal Canal & Right ischiorectal fossa
The anal canal columns' are found in the upper 2/3 of the anal canal(folds
of the mucosa).
Dr Ndayisaba Corneille 22

23. Cloacal part of the rectum.
• It is endodermal in origin.
• The mucus membrane is typical large gut with columnar
epithelium.
• There are mucus glands in the submucosa
• Arterial supply; It is from the superior rectal artery as far as
the white line. The sphincters outside the mucus
membrane are supplied by the middle or inferior rectal
arteries.
• The veins drain upward in the in the sub mucus plexus of
the ampulla
• Lymphatics pass upwards to the inferior mesenteric of pre
aortic lymph nodes.
• The nerves are from the pelvic plexus (autonomic)
Dr Ndayisaba Corneille 23

24. Anal canal cont.
• Above the anal valves , the longitudinal mucus
folds extend upwards in the anal canal and
reach the lower limit of the rectum.
• The contain sub mucus veins and are named
anal columns.
Dr Ndayisaba Corneille 24

25. .Anal part
• It is ectodermal in origin with thin hairless
skin. It is covered with stratified squamous
epithelium.
• Arterial supply inferior rectal artery.
• Venous drainage inferior rectal vein (systemic)
• LYMPHATICS drain into the medial group of
superficial inguinal lymph nodes.
• Nerves inferior rectal nerve (somatic)
Dr Ndayisaba Corneille 25

26. Blood supply to the rectum and
anal canal.
Dr Ndayisaba Corneille 26

27. ANAL SPHINCTERS
• AT the beginning of the anal canal, the inner circular
layer becomes greatly thickened forming the internal
sphincter, and this stops at the white line of Hilton.
• The longitudinal layer thins out, and from it arise inter
muscular septa ( fibro elastic fibers)
• The external sphincter lines the entire length of the
anal canal. It is striated muscle. It is made up of 3 parts
1)subcutaneous external. sphincter-lies in the perianal
fat 2)superficial external sphincter- it is elliptical. Its
anterior part is attached to the perineal body and the
posterior part attached to the anal coccygeal body.
3)deep external sphincter
Dr Ndayisaba Corneille 27

28. Anal sphincters
• The anal canal is always closed except during
the passing of stool and flatus.
• The whole extent of the canal (1.5”) is
enclosed in a sphincteric tube of muscle. The
internal and external sphincter. Each occupies
2/3 of the anal canal so that they overlap in
the middle 1/3.
• The internal sphincter is smooth muscle
(visceral) and lies around the upper 2/3 of the
anal canal. Dr Ndayisaba Corneille 28

29. External anal sphincters
Dr Ndayisaba Corneille 29

30. Internal sphincter
• Occupies the upper 2/3s of the anal canal i.e.
down to the Hiltons line. It is the thickened
lower end of (inner) circular layer of the gut.
• The sphincter is not competent when acting
alone.
Dr Ndayisaba Corneille 30

31. • Pubo rectalis is thickened lower border of
levetor ani and when it contracts ,it increases
the angle between the rectum and the anal
canal.
• FUNCTIONALLY THE EXTERNAL SPHINCTER is
the most important.
Dr Ndayisaba Corneille 31

32. THE ANAL CANAL
Dr Ndayisaba Corneille 32

33. VEINS OF THE ANAL CANAL
Dr Ndayisaba Corneille 33

34. VEINS OF THE ANAL CANAL
• 3 OF THE VEINS SITUATED AT 4,7,11 OCLOCK
are apt to become varicose as the 3 primary
hemorrhoids.
• Superior and middle rectal veins take blood to
the inferior rectal vein.
Dr Ndayisaba Corneille 34

35. Mucus membrane of the anal
canal.
• Cloacal part ,endodermal in origin, covered
with large gut mucus membrane, columnar
epithelium.
Dr Ndayisaba Corneille 35

36. Dr Ndayisaba Corneille 36

37. Fissure in ano
Dr Ndayisaba Corneille 37

38. Internal haemorroid
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39. Rectal piles
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40. Dr Ndayisaba Corneille 40

41. Dr Ndayisaba Corneille 41

42. END
Dr Ndayisaba Corneille
THANKS FOR LISTENING
By
DR NDAYISABA CORNEILLE
MBChB,DCM,BCSIT,CCNA
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