ANATOMY OF ANAL CANAL AND PATHLOGY

1. Dr.I.David Thanka Edison ,MS;
Assistant Professor
Department of General Surgery.

2. Objective to Learn:
 Gross Anatomy of Anal Canal
 Examination & Investigation in Anal canal
 Anal fissure- Causes, Types & Management
 Fistula in Ano- Causes, Types & Management.

3. Anal canal Anatomy:

4. Anal Canal
 Length= 3.8 to 4.0 cm
 Zona Columnaris: Upper ½- lined by Simple columnar
 Zona Hemorrhagica: Upper part of lower half ( above the
Hilton’s white line) – Stratified squamous non-keratinizing
epithelium
 Zona Cutanea: Lower part of lower half( below the
Hilton’s white line)- Stratified squamous keratinizing
epithelium

6. Pectinate line
(dentate line)
anal sinus
anal valve
Remnanats of
Proctodeal M.

7. External & Internal Sphincter:
External Sphincter Internal Sphincter
Muscle Single muscle k/as Goligher
Muscle
Continue of the Circular muscular
coat of the rectum
Color Red Pearly white
Nerve Pudendal Nerve Autonomic nervous system-
Intrinsic non-adrenergic & non-
cholinergic fiber
Types of
Muscle
Somatic Voluntary Muscle Non-striated Involuntary Muscle
Parts/fts Deep, Superficial and
Subcutaneous portion
Always lie in the tonic state of
contraction

8. Blood Supply of Anal Canal
 Superior Rectal Artery Right & Left Branch
 Middle Rectal Artery
 Inferior Rectal Artery
Superior R.A
Middle R.A
Inferior. R.A

9. Venous Drainage:
Upper Half- Superior Rectal Vein IMV Porto
mesenteric venous system
- Middle rectal vein Internal Iliac Vein
Lower Half- Inferior rectal vein & Subcutaneous peri -
anal plexus of veins Internal Iliac Vein
Lymphatic Drainage:
Upper Half- Post Rectal LN Para aortic nodes
Lower Half- Superficial Deep Inguinal LN

10. Venous system of Anal Canal:
SUPERIOR RECTAL
VEIN
MIDDLE RECTAL
VEIN
INFERIOR
RECTAL VEIN

11. Examination of Anal Canal:
 Relaxed Patient
 Informed Consent
 Private environment
 Good Light
 Position – Left Lateral Position/ Sims’s Position- most
commonly used.

12. Sim’s PositionSim’s position

13. P/R Examination:Inspection
 Skin Lesion- Psoriasis
-Lichen planus
- Warts
-Candidiasis&Herpes simplex
 Whether anus is closed
or patulous
 Position of the anus/perineum
 Evidence of piles/
sentinel tag
( Anal fissure or SCC) Psoriasis

14. P/R:Gloves,jelly etc………
 Posterior surface of the prostate gland with median
sulcus( Male) & Uterine cervix( in female)-Anteriorly.
 Intrarectal, Intraanal or extraluminal mass.
 Sphincter length
 Resting tone
 Voluntary squeeze
 Examining finger – Mucus, Blood, Pus
 Stool Color.

15. Proctoscope:

16. Proctoscopy:
 Position: Left lateral position
 Inspection of the distal rectum and anal canal
 Injection in Hemorrhoids
 Banding of Piles mass
 Biopsy of mass

17. Anal Fissure:
 Longitudinal tear in the anal canal
 Site: Posterior midline (90%) and Anterior midline in
10% case especially in female.

18. Etiology & Predisposing factors of
Anal Fissure:
 Age: Young adult & middle aged man
 Gender : Male > Female
 Posterior midline is the commonest site because-
-Maximum stretching on this site
- Less tissue here
-Minimal tissue perfusion

19. Etiology of Anal Fissure
 Main cause-Trauma–Strained evacuation of Hard stool
or
 Less commonly - Repeated passage of stool ( diarrhea)
 Anterior anal fissure in 10% cases – Mostly in Women
that occurs following vaginal delivery

20. Predisposing Factors: FISSURE
 Faces – Hard
 Ischemia
 Surgical procedure- Haemorrhoidectomy
 Sphincter hypertonia
 Underlying disease – Crohn’s , TB, L.V, Syphilis etc
 Repeated Childbirth
 Enthusiastic usage of ointments and abuse of luxatives.

21. C/F of Anal Fissure:
 Severe anal pain during the defecation
 Blood streak outside the stool
 Bleeding P/R- Bright
 Mucous Discharge
 Constipation
 Itching

22. Chronic Anal Fissure: Findings:
 Hypertrophied Anal Papilla- Proximally
 Sentinel tag- Distally
 Thickened edge
 Exposed internal sphincter i.e Ulcer overlying the
fibers of internal sphincter

23. Confirmation of Diagnosis:
 Adequate clinical examination under G/A
 Proctoscopy
 Sigmoidoscopy
 Take Biopsy
 Do Culture

24. Treatment: Conservative & Surgical
 Conservative treatment helpful in most of cases
 Main objective to treat Constipation.
-Add the fiber to the diet
-Encourage water intake
-Laxative to make the stool soft
 Application of local anesthetic- Lignocaine jelly
 Antibiotics- Ofloxacine + Orinidazole

25. Conservative :Hot Seitz Bath

26. Conservative Treatment:
 Drugs that release the Nitric oxide donor- Glyceryl
Trinitrate( GTN) 0.2 % & Diltiazam 2%.
 GTN 0.2% - QID at Anal Margin
- S/E- Headache and Recurrence
 Diltiazam 2%- BD at anal margin
 - M/A- Produces NO – Relaxation of the internal
Sphincter- reduces the spasm, pain & Increase the vascular
perfusion to promotes healing

27. Conservative Treatment
 Botulinum toxin injection
 Site of Inj- Internal Sphincter
 M/A- Inhibits presynaptic release of Ach from
cholinergic nerve endings- Paresis of Striated muscle
and release the spasm .

28. Operative procedure for FIA.
 Anal Dilatation
 Posterior division of the exposed fibers of the internal
sphincter in the base of the fissure.
 Lateral Anal Sphincterotomy of Notaras
 Anal advancement Flap

29. Anal Dilatation: Lord’s Anal
Dilatation
 Position- Lithotomy
 Under G/A
 Manual 4 to 8 finger sphincter dilatation
 Useful in Young men with very high sphincter tone
 Risk: Incontinence.

30. Lateral Anal Sphincterotomy:
 Position- Lithotomy
 Anesthesia- Regional or G.A
 Palpate the distal internal sphincter with the help of
bivalved speculum at the intersphincteric groove.
 Give a small longitudinal incision in right or left lateral
position

31. Lateral Anal Sphincterotomy
Cut the Mucosa
Get the sub- mucosal & Intersphincteric planes
Allow the Exposure of Internal sphincter
Cut the Internal sphincter up to the apex of the fissure
Closed the wound with the absorbable suture

32. Complications of LAS:
 Hemorrhage
 Hematoma
 Bruising
 Perianal Abscess
 Fistula
 Incontinence.

33. Fistula-in-ano:
 Chronic abnormal communication
 Between the Internal opening (anorectal lumen) &
External opening on the skin of the perineum or
buttock
 Lining is Granulation tissue.
 Commonest cause – Non-specific, Idiopathic & Crypto
glandular & Inter-Sphincteric anal gland infection.

34. Fistula-in-ano:Aetiopathogenesis
Persistent anal gland Infection
Anorectal Abscess
Rupture inside as well as outside
Fistula

35. Fistula-in-ano:Underlying[other
causes] Condition –CISTULA+ ARF
Carcinoma
Ileitis-Crohn’s
Schistosomiasis
Tuberculosis
Ulcerative colitis
L. Venereum
Anal Fissure
Abscess
Actinomycosis
Rectal Duplication
Foreign Body

36. Fistula-in-ano:Clinical features
 Intermittent purulent discharge
 Pain
 External opening as sinus or Ulcer
 Bleeding/PR(sometimes)

37. Types of Fistula in ano:Standard
 Low type- Internal opening below the anorectal ring.
 High Type-Internal opening above the anorectal ring.

38. Park’s Classification:
 Based on relationship of fistulous tract to the anal
sphincters- 4 types.
 Intersphincteric Fistula
In vast majority of Cases.
 Trans sphincteric Fistula
 Supra Sphincteric Fistula
 Extra Sphincteric Fistula

39. Park’s Classification

40. Intersphincteric Fistula:
 Most common type
 Incidence= 45%
 Don’t cross the external sphincter

41. Trans-sphincteric Fistula:
 2nd Most common type
 Incidence=40%
 It’s track crosses both external & Internal sphincter
 Passes through the Ischio-rectal fossa to reach the
skin of the buttock

42. Supra-sphincteric Fistula:
 Very Rare
 Cause- Iatrogenic
 Very similar to high level
T-S Type.

43. Clinical Assessment/Investigation
Important point about fistula
1. Site of the internal opening & External opening.
2. Course of the primary track
3. Presence of the secondary extension
4. Presence of other associated condition.

44. Goodsall’s Rule:

45. Clinical Assessment/Investigation
Hydrogen peroxide
injection:
-Inject through the
external opening
-Find out the site
of internal opening

46. Clinical Assessment/Investigation
Gentle use of Probe

47. Clinical Assessment/Investigation
Manometry:
- Resting anal tone
- Functional anal sphincter length
- Voluntary squeeze

48. Endoluminal USG: Sphincter
integrity, tract & anal canal.

49. MRI :
 Gold Standard
 Demonstrate the
secondary extension

50. Fistulography:

51. Demonstration of Fistula in Ano on
CT

52. Management : Fistula in Ano:
 Fistulotomy
 Fistulectomy
 Setons- Loose & Tight Setons
 Biological Agent- Fibrin Glue
 Advancement Flap- To preserve both anatomy & Function .
 VAAFT: Video Assisted Anal Fistula Treatment.

53. Fistulotomy
 Laid open the track( John of Arderne)
 Indication : Intersphincteric & Transsphincteric
Fistula.
 Steps:
1. - Position - Lithotomy
2. - Anesthesia - G/A.
3. -Identified the internal opening

54. Fistulotomy: Steps Continue
4. Pass the probe through
E.O to E.O to the I.O
5. The track is laid open over
the probe.
6. Curette the granulation
tissue and sent for HPE.
7.Wound edges are trimmed
E.O
I.O
Probe
Laid
open

55. Fistulotomy:

56. FISTULECTOMY: Excision of
whole Fistulous tract:
Probe

57. Setons
 Thread
 Wire
 Proline
 Infant feeding tube
 Ksharsutra: kshar- corrosive & Sutra- Thread

58. Setons: Loose :
seton
Non-absorbable
Non-Degradable
Comfortable
No intent to cut
Ideal seton
No
tension

59. Purpose to use of Loose Setons:
Purpose:
- Eradicate the acute sepsis & Secondary extension
- To simplify the fistula
- Allow fibrosis

60. Tight/Cutting Seton
 Placed with intention to cut the enclosed muscles.
 Also k/as “ Cheese Wiring through the ice”
 Fistulous tract is replaced by a thin line of fibrosis.
 Types- Elastic & Self cutting
- Non elastic & tightened

61. Cuting & healing simultaneously.

62. Biological Agent to fill the fistula.

63. Insertion of Fibrin Glue in the
fistula

64. VAAFT:Video Assisted Anal Fistula
Treatment
 Visualization of the F.tract with the Fistuloscope
 Aim is to find the correct position of Internal Opening.
 A stapler to close the Internal opening.
 Fistuloscopy is done under irrigation & F.tract as well as all
granulation tissues are coagulated
 Total closure of the Internal opening with inserting the
Cyanoacrylate

65. Home message:Fissure:
 Post-midline is the commonest site for Fissure ( 90% )
 Main cause is Constipation – hard stool i.e trauma
 Pain during defecation is the commonest complaint.
 Clinical examination is sufficient to diagnose it
 GTN & Diltiazam 2% local application along with diet
modification have an excellent result as equivalent to LAS.
FISTULA IN ANO:
 Persistent anal gland infection is the commonest cause of
Fistula in Ano

66. Home message:
 Goodsall’s rule is very useful in determining the site of external &
internal opening as well as about the fistulous tract.
 Intersphincteric type of fistula in Ano is the commonest type
( 45%)
 MRI is the gold standard for fistula imaging in complicated fistula
 Fistulotomy and Fistulectomy are common procedure to treat it.
 VAAFT is the recent advance in Fistula surgery