pictroral presentation

1. Dr. Nabarun Biswas
Indoor Medical Officer
Surgery Unit -2, MMCH

2. Anus & Anal Canal
• It is the
lowest part of
GIT that
begins at the
level where
the rectum
passes
through the
pelvic
diaphragm &
ends at the
anal verge

3. Embryology

4. Interior

5. Interior in detail

6. Musculature

8. Pubo-rectalis muscle

9. Sphincters of anus

10. Rectum

11. 1 inch infront of
coccyx
Location and peritoneal relations of
the rectum
S3

12. Shape (flexures) of the rectum
- Antero-posterior curve
- 3 flexures
1. Upper concave to left
2. lower concave to left
3. Middle concave to right
Rectal ampulla

13. Anterior relations of the rectum

14. Posterior relations of the rectum

15. Arterial supply of ano-rectum

16. Venous
drainage

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

19. 11 o’clock
7 o’clock
3 o’clock

20. Lymphatic drainage of anus

21. Lymphatic drainage of rectum

22. Nerve supply of the anus
• Pudendal nerve (S2-4)
• Sensory; internal pudendal
• Motor
• Internal sphincter; sympathetic &
parasympathetic
• External sphincter; inferior rectal
branch of internal pudendal n,
perineal branch of S4

23. Nerve supply of the rectum
• Sympathetic L1-3
• Parasympathetic S2-4
• The hypogastric plexus
• Pelvic plexus

24. Nerve supply

25. Physiology of defecation
• It is the final act of digestion by which
body eliminate solid, semisolid or liquid
waste material from digestive tract.
• Sensation: receptive relaxation of the
rectum, anal sampling, recto-anal reflex
• Center: S2-4, cortical
• Effectors: sphincters, rectal contraction,
abdominal muscles, levator ani

26. Defecation

27. Continence mechanism
1. Internal sphincter; involuntary, resting
tone
2. External sphincter; voluntary, squeeze
pressure
3. Levator ani
4. Anorectal angle
5. Anal cushions