The rectum is the lowest part of the gastrointestinal tract, extending from the sigmoid colon to the anal canal. It has two anteroposterior and three lateral curvatures and receives its blood supply from the inferior mesenteric artery. The anal canal extends from the anorectal junction to the anus. It contains two sphincter muscles - the internal anal sphincter, which is involuntary, and the external anal sphincter, which is voluntary.

1. Rectum
• The lowest part of gastrointestinal tract is formed by
the rectum and anal canal
• Anus  external opening of anal canal
(12 cm)

3. Situation /extent

4. Rectal ampulla

5. Course and direction
• Downwards, backwards downwardsdownwards,forwards

6. Curvatures
• Two anteroposterior
• Three lateral
Anteroposterior curves Lateral curves

7. Relations
• Peritoneal relations
M
U
L

8. Visceral relations
• Anterior (male)
Rectovesical pouch

9. • Anterior (female)

10. • Posterior relation 

11. Mucosal folds
• Longitudinal folds transitory, lower part
• Transverse folds/Houston’s valves/plicae transversales
upper
middle
lower

12. Functional parts of rectum

13. Arterial supply
Inferior mesenteric artery

14. • Superior rectal artery
• Middle rectal arteries
• Median sacral arteries  supply the posterior
wall of anorectal junction

15. Venous drainage

16. Lymphatic drainage

17. Lymphatic drainage
• From upper half  inferior mesenteric nodes
• Lower half  internal iliac nodes

18. Nerve supply
• Sympathetic (L1, L2)
Inhibitory to rectal musculature and motor to
internal sphincter
• Parasympathetic (S2, S3,S4)


19. Support of rectum
• Pelvic floor
• Fascia of Waldeyer
• Lateral ligaments of rectum
• Rectovesical fascia of Denonvilliers
• Pelvic peritoneum
• Perineal body

20. Clinical anatomy
• Digital per rectum examination
• Proctoscopy and sigmoidoscopy
• Prolapse of rectum
• Carcinoma

21. Anal canal
• Terminal part of the large intestine
• Situated below the level of pelvic diaphragm
• 3.8 cm long
• Extends from anorectal junction to the anus

22. Relations
• Anterior 
• Posterior 
• Laterally  ischiorectal fossae

23. • All round  anal canal is surrounded by the
sphincter muscles, the tone of which keeps
the canal closed

24. Interior of anal canal
(15mm)
8-10mm
Of Morgagni

25. Interior of anal canal
(15mm)
8-10mm
Of Morgagni
Upper part

26. Interior of anal canal
(15mm)
8-10mm
Of Morgagni
• Middle part (pecten)

27. Interior of anal canal
(15mm)
8-10mm
Of Morgagni
• lower part (cutaneous)

28. Anal sphincters
• Internal anal sphincter  involuntary
• External anal sphincter  voluntary

29. • Anorectal ring it is formed by the fusion of
puborectalis , deep external sphincter and the
internal sphincter
• Rectal incontinence

30. Arterial supply
• Above the pectinate line  sup. Rectal art.
• Below the pectinate line  inf. Rectal art.

31. Venous drainage
• Internal rectal venous plexus or haemorrhoidal
plexus lies in the Submucosa above the pectinate
line  superior rectal vein
• Veins present in the three anal columns at 3,7,
and 11 o’clock position are large  Primary
internal piles

33. • External piles below the pectinate line
• Painful
• Do not bleed at stool

34. • External rectal venous plexus lies outside the
muscular coat of the rectum and anal canal

35. Nerve supply
• Above the pectinate line 
Symp. L1,L2
P.symp.  S2,S3,S4
Below the pectinate line inferior rectal nerve
(somatic) S2,S3,S4

36. • SPHINCTERS
• Internal sphin.  symp.( contraction) ,
p. symp. (relax)
• External sphin.  inferior rectal nerve,
perineal branch of fourth sacral nerve