The document provides an overview of anal conditions, covering the embryology, anatomy, histology, physiology, and diseases of the anal canal. It discusses the development of the anal canal from endoderm and ectoderm. Key topics include the internal and external anal sphincters, hemorrhoids, anal fissures, abscesses, fistulas, and anal cancer. Treatment approaches are outlined for various anal diseases.

1. Anal Conditions

2. Objectives
• Embryology
• Anatomy
• Histology
• Physiology
• Diseases of the Anal Canal

3. Embryology
Anal canal develops from the endoderm and ectoderm (proctodeum)
Urorectal Septum:
Separates the cloche into the anal canal and urogenital sinus
Fuses with the cloacal membrane and separates it into the anal membrane and
the urogenital membrane
Proctodeum:
mesenchyme raises the surrounding ectoderm to form a shallow anal pit
Separated by the dentate line
Blood supply, lymphatics, innervation in the anal canal depend on the embryonic
origin

4. Embryology

5. Embryology
• A

6. Embryology

7. Anatomy
• Surgical vs Anatomical Anal Canal
• Blood supply
• Lymphatics
• Muscles and Innervation

8. Embryology
• A

9. Embryology
• A

10. Embryology
• A

11. Embryology
• A

12. Embryology
• A

13. Embryology
• A

14. Embryology
• A

15. Embryology
• A

16. Anatomy
Above Dentate Line Below Dentate Line
Arterial Supply
Superior Rectal A.
(IMA)
Middle Rectal A.
Inferior Rectal A.
(Internal Pudendal)
Venous Drainage Superior and Middle Rectal Vs. Inferior Rectal V.
Lymphatic Drainage
Internal Iliac and Inferior
Mesenteric LNs.
Superficial Inguinal LNs.
Sphincter/Innervation
Internal Sphincter
(Autonomic Ns.)
External Sphincter
(Pudendal N.)
Sensory Not sensitive to pain Very sensitive to pain

17. Histology
Rectum: Simple Columnar epithelial cells with goblet cells
Anus:
Above “White Hilton’s Line”: Non-keratinized stratified squamous
epithelial cells
Below “White Hilton’s Line”: Keratinized stratified squamous epithelial

18. Histology

19. Physiology
Tow Sphincters close the anal canal:
Internal Sphincter: Hypertrophied part of the circular layer of the muscularis:
 Smooth muscles
 Autonomic innervation (Sympathetic “contraction”, Parasympathetic “relaxation”
 Opens when the rectum is distended (rectoanal inhibitory reflex)
 contributes 55% of the resting pressure
External Sphincter: skeletal muscle that surrounds the anal canal
 Striated muscles
 Somatic innervation
 Voluntary control
 3 layers: deep, superficial, subcutaneous
Both sphincters are in continuous contraction

20. Anal Diseases
Hemorrhoids
Anal Fissures
Anorectal Sepsis and Cryptoglandular Abscess
Fistula In Ano
Pilonidal Disease “cyst, infection”
Perianal Dermatitis
Hidradenitis Suppurativa
Anal Sphincter Injury and Incontinence
Anal Cancer

21. Hemorrhoids “Rectal varices”
Hemorrhoids are cushions of submucosal tissue containing venules, arterioles, and
smooth muscle fibers that are located in the anal canal
3 cushions: left lateral, right anterior, and right posterior positions
skin tag: is redundant fibrotic skin at the anal verge, often persisting as the residual of
a thrombosed external hemorrhoid
3 Types:
External hemorrhoids: distal to the dentate line and are covered with anoderm
Internal hemorrhoids: proximal to the dentate line
Combined internal and external hemorrhoids

24. Hemorrhoids “Rectal varices”
Degrees:
1st degree hemorrhoids: may prolapse beyond the dentate line on straining
2nd degree hemorrhoids: prolapse, reduce spontaneously
3rd degree hemorrhoids: prolapse, require manual reduction
4th degree hemorrhoids: prolapse, cannot be reduced
risk for strangulation
Sings and Symptoms:
Asymptomatic
Pain, bleeding, prolapse mass, thrombosis
Portal hypertension

25. Hemorrhoids “Rectal varices”
Risk Factors:
Low-Fiber Diet
Constipation
Prolonged Straining
Pregnancy
Portal Hypertension
Increased Pelvis pressure

26. Hemorrhoids “Rectal varices”
Treatment:
 Is only indicated if they become symptomatic
Medical Therapy: diet, pain control, laxatives, paths
Rubber Band Ligation
Infrared Photocoagulation
Sclerotherapy
Excision of Thrombosed External Hemorrhoids
Doppler-Guided Hemorrhoidal Artery Ligation
Hemorrhoidectomy “Treatment of choice”

27. Hemorrhoids “Rectal varices”
Complications of Hemorrhoidectomy:
Post-operative pain
Urinary retention
Fecal impaction due to pain
Bleeding, may be massive
Infection
transient incontinence to flatus
Permanent fecal incontinence
anal stenosis
Ectropion “Whitehead’s deformity”

31. Anal Fissures “Anal Tears”
Pathophysiology:
Related to trauma to the anus (hard stool, prolonged diarrhea)
A tear in the anoderm causes spasm of the internal anal sphincter, which results in
pain, increased tearing, and decreased blood supply to the anoderm
85% midline posterior, 15% midline anterior, less than 1% off midline
Types:
acute fissure: is a superficial tear of the distal anoderm and almost always heals with
medical management
Chronic fissures: develop ulceration and heaped-up edges with the white fibers of
the internal anal sphincter visible at the base of the ulcer

32. Anal Fissures “Anal Tears”
pain with

33. Anal Fissures “Anal Tears”
pain with

34. Anal Fissures “Anal Tears”
Signs and Symptoms:
tearing pain with defecation
 hematochezia
intense and painful anal spasm lasting for several hours after a bowel movement
skin tag and/or a hypertrophied anal papilla internally
No PR
Lateral fissures may be:
Chron’s Disease
HIV
Syphilis
TB
Leukemia

35. Anal Fissures “Anal Tears”
Treatment:
Reduce anal Trauma
 Medical therapy: reduce pain, improve blood supply
 is effective in most acute fissures, but will heal only approximately 50%
of chronic fissures
Local anesthesia
Nitroglycerin ointment
calcium channel blockers
Arginine
bethanechol
Surgical Treatment: lateral internal sphincterotomy is the procedure of
choice (30% of the internal sphincter ), or advancement flaps
 95% success rate

36. Anal Fissures “Anal Tears”

37. Anal Fissures “Anal Tears”
pain with

38. Anal Fissures “Anal Tears”
Complication:
Recurrence
Incontinence
Infection

39. Anorectal Sepsis and Cryptoglandular Abscess
Infection of an anal gland results in the formation of an abscess
Different spaces may be involved:
perianal abscess (M.C)
Intersphincteric abscesses
Ischiorectal Abscess
Pelvic abscesses
supralevator abscesses
Signs and Symptoms:
painful swelling at the anal verge
Inflammation signs and symptoms
urinary retention
Life-threatening sepsis

40. Anal Fissures “Anal Tears”
pain with

42. Anal Fissures “Anal Tears”
pain with

43. Anorectal Sepsis and Cryptoglandular Abscess
Treatment:
I&D as soon as the diagnosis is established
Antibiotics are only indicated if:
extensive overlying cellulitis
Immunocompromised
diabetes mellitus
valvular heart disease

45. Anorectal Sepsis and Cryptoglandular Abscess
Notes:
Perianal Sepsis in the Immunocompromised Patient
 The immunocompromised patient with perianal pain presents a diagnostic dilemma
No Signs & Symptoms of inflammation
Examination under anesthesia should not be delayed due to neutropenia
I&D + ATB

46. Anorectal Sepsis and Cryptoglandular Abscess
Necrotizing Soft Tissue Infection of the Perineum:
necrotic skin, bullae, or crepitus
high index of suspicion is necessary because perineal signs of severe infection
may be minimal
Surgical debridement + ATB
May require colostomy
High mortality (50%)
50% of patients develop fistula after treatment of cryptoglandular abscess
The fistula usually originates in the infected crypt (internal opening) and
tracks to the external opening, usually the site of prior drainage

47. Fistula In Ano
Fistula: abnormal connection between two types of epithelium
Causes:
Cryptoglandular abscess (M.C)
Trauma
Crohn’s disease
Malignancy
Radiation
Unusual infections (tuberculosis, actinomycosis, and chlamydia) may
also produce fistulas

48. Fistula In Ano
Symptoms and Findings:
persistent drainage from the internal and/or external openings
External opening as a red elevation of granulation tissue
Hydrogen peroxide or dilute methylene blue test may be used
Goodsall’s rule:
fistulas with an external opening anteriorly connect to the internal opening
a short, radial tract
Fistulas with an external opening posteriorly track in a curvilinear fashion to
the posterior midline
exceptions to this rule often occur if an anterior external opening is greater
than 3 cm from the anal margin (track to the posterior midline)

49. Fistula In Ano

50. Fistula In Ano
4 major categories of fistulae:
Inter-sphincteric
Trans-sphincteric
Supra-sphincteric
Extra-sphincteric

51. Fistula In Ano

52. Fistula In Ano

53. Fistula In Ano
Treatment:
Depend on the internal and external openings location and the involvement of the
sphincter complex
Intersphincteric needs only fistulotomy
Transsphincteric and suprasphincteric require Seton before fistulotomy
• up to 30% loss of sphincter is accepted
• Seton drains, cutting setons, non-cutting setons
Extrasphincteric, the portion of the fistula outside the sphincter should be opened
and drained
endorectal advancement flap
Fibrin glue
Ligation of the intersphincteric fistula tract (LIFT)

54. Fistula In Ano
Rectovaginal fistula: connection between the vagina and the rectum or anal canal proximal
to the dentate line
Classification:
Low: opens in the fourchette
Middle: opens between the fourchette and cervix
High: opens near the cervix
Causes:
After surgical resection of a midrectal neoplasm
Radiation injury
Extension of an undrained abscess.
Complicated diverticulitis
Crohn’s disease

55. Fistula In Ano
Diagnosis:
sensation of passing flatus from the vagina to the passage of solid
stool from the vagina
some degree of fecal incontinence
vaginitis
barium enema or vaginogram
methylene blue
Treatment: depends on the size, location, etiology, and condition of surrounding tissues
Low and mid-rectovaginal fistulas: best with endorectal advancement flap +/-
overlapping sphinectroplasty
High-rectovaginal fistulas: transabdominal approach (resection with closure)

56. Fistula In Ano

57. Pilonidal Disease “cyst, infection”
Hair-containing sinus or abscess occurring in the intergluteal cleft
May become infected
Etiology: unknown
Diagnosis:
Inflammatory signs with a tough swelling
Treatment:
Incision and drainage
Excision
Wound care

59. Perianal Dermatitis
Pruritus ani: severe perianal itching
Surgical causes:
Hemorrhoids
Ectropion
Fissure
Fistula
Neoplasms
Other causes:
Perianal infection (Bacterial, fungal, viral, parasitic)
Noninfectious dermatologic causes: seborrhea, psoriasis, and contact
dermatitis
Systemic diseases: DM, Jaundice

60. Perianal Dermatitis
Idiopathic and probably related to local hygiene, neurogenic, psychogenic (M.C)
Treatment:
removal of irritants
improving perianal hygiene
dietary adjustments
avoiding scratching
Local medications
If chronic or not responding to treatment, may require a biopsy

61. Hidradenitis Suppurativa
Infection of the cutaneous apocrine sweat glands
Mimic complex anal fistula disease, but stops at the anal verge because there are no apocrine
glands in the anal canal
Treatment:
incision and drainage of acute abscesses
unroofing of all chronically inflamed fistulas and debridement of granulation tissue
Radical excision

62. Anal Sphincter Injury and Incontinence
The most common cause of anal sphincter injury is obstetric trauma during vaginal
delivery
Rectal injury accompanied by sphincter injury should be treated with fecal diversion and
distal rectal washout, with or without drain placement
Treatment: for isolated sphincter injury
wrap-around sphincteroplasty
Postanal intersphincteric levatorplasty
Gracilis muscle transposition with or without chronic, low-frequency
electrostimulation
Artificial anal sphincter
Sacral nerve stimulation
Fecal diversion

65. Anal Cancer
Rare
Risk Factors:
Human papillomavirus (HPV)
Human immunodeficiency virus (HIV)
Cigarette smoking
Multiple sexual partners
Anal intercourse
Immunosuppressed state
Signs and Symptoms:
Often asymptomatic
Bleeding, lump, itching, ulcer

66. Anal Cancer
Diagnosis: Biopsy
 Anal margin tumors:
 Squamous cells carcinoma
 Basal cells carcinoma
 Paget’s disease “ eczema-like rash of the skin, associated with underlying tumor”
 Bowen’s disease “squamous cell carcinoma in situ”
 Anal canal tumors:
 squamous cell carcinoma
 transitional cell/cloacogenic carcinoma
 malignant melanoma

67. Anal Cancer
Treatment:
 Epidermoid carcinoma of anal canal: Chemoradiation is mainstay—5-FU, mitomycin C,
and external beam radiation (Nigro protocol) surgery is reserved or recurrence
 Other anal margin tumors: Wide local excision alone or in combination with
radiation and/or chemotherapy is successful in 80% o cases without abdominalperineal
resection (APR) if tumor is small and not deeply invasive
 Anal canal tumors: Local excision not an option; combined chemotherapy
(5-FU and mitomycin C) with radiation o ten successful; APR if chemoradiation fails

68. Anal Cancer
Prognosis:
 Anal margin tumors: 80% overall 5-year survival
 Anal canal tumors:
 Epidermoid carcinoma: 50% overall 5-year survival
 Malignant melanoma: 10–15% 5-year survival.

69. Anal Cancer
Melanoma

70. Anal Cancer
Squamous Cell Carcinoma