1. Rectum & Anal canal

2. Objectives Discuss the anatomical structure of the rectum.
Describe the anatomical structure of the anal canal.
Give the blood supply of rectum and anal canal.
Define external and internal hemorrhoids.

3. Rectum

4. Location and peritoneal relations of the rectum
12 cm
1 inch infront of coccyx

5. Shape (flexures) of the rectum
- Anteroposterior curve
- 3 flexures
Upper concave to left
lower concave to left
Middle concave to right
Rectal ampulla

6. Rectum

7. Relations of rectum

8. Anterior relations of the rectum

9. Posterior relations of the rectum

10. Per rectal (PR) examination
Knee-chest position
Index finger introduced into lower rectum through anal orifice
Structures palpated
Anterior
Posterior
On each side

11. Blood supply of rectum

12. Arterial supply of the rectum and anal canal
median sacral artery
superior rectal artery
(inferior mesenteric)
middle rectal artery
(internal iliac)
inferior rectal artery
(internal pudendal)

13. Arteries of the rectum and anal canal
Superior rectal
Middle rectal
Inferior rectal
Median sacral

15. Veins of the rectum

16. Hemorrhoids Internal hemorrhoids External hemorrhoids
Tributary of sup rectal
Above white line
Generally painless
External hemorrhoids
Tributary of inf rectal
Below white line
Generally painful

18. 11 o’clock
7 o’clock
3 o’clock

19. Lymph drainage of rectum:
Upper half drains to para rectal L.Ns which drain to inferior mesenteric L.Ns.
Lower half drains to internal iliac lymph nodes.

20. Lymphatic drainage of the rectum

21. Anal canal
Beginning: It begins one inch below and anterior to the tip of the coccyx at the recto-anal junction.
Course: It runs down and backwards.
Termination: It ends at the anus.
Relations:
Laterally: Ischioanal fossae.
Posteriorly: Anococcygeal raphe between it and tip of coccyx.
Anteriorly: Perineal body between it and bulb of penis in males Perineal body between it and vagina in females.

22. anal sinus
anal valve
Pectinate line
(dentate line)

23. Blood supply, nerve supply and lymph drainage of anal canal:
Upper part
Lower part
Blood supply
-It is supplied by superior rectal artery.
- It is drained by superior rectal vein (portal circulation).
-It is supplied by:
1- Middle rectal artery of internal iliac artery.
Inferior rectal artery of internal pudendal artery.
-The corresponding veins drain into internal iliac vein (systemic circulation.)
Nerve supply
Above pectinate line by autonomic nerve fibers.
Below pectinate line by inferior rectal nerve (Sensitive to pain &touch).
Lymphatic drainage
Above pectinate line into internal iliac LNs.
Below the pectinate line into superficial inguinal LNs.

24. Anal sphincters:
Internal anal sphincter: -It is the thickened inner involuntary circular muscle layer of the anal canal. -Surrounds the upper 3/4th of the anal canal, extending from ano-rectal junction till the white line (Hilton’s line). Nerve supply: autonomic External anal sphincter: -Striated voluntary muscle fibers. -Surrounds the whole length of the anal canal outside the internal anal sphincter. -Parts: I) Subcutaneous Part: -Surrounds the anus just under the perianal skin. -Attached to perineal body &anococcygeal raphe. II) Superficial Part: -Surrounds the lower part of the internal sphincter above the subcutaneous part. III) Deep Part

25. Relations of the Anal Canal
The anal canal is related:
posteriorly to the fibrous tissue between it and the coccyx (anococcygeal body),
laterally to the ischiorectal fossae containing fat,
anteriorly to the perineal body separating it from the bulb
of the urethra in the male or the lower vagina in the female.

26. anal sinus
anal valve
Pectinate line
(dentate line)

27. Sphincters of the anal canal1 2

28. The external sphincter
(voluntary)

29. Vessels and nerves of the anal canal
2 cm
1 ½ cm
½ cm

30. THANK YOU