Name - Nikhil Gupta
Roll.No.- 41
Batch- 2022-2023
Guided by- Dr.Amit Singh (H.O.D)
Dr.Varsha Gupta
JEEVAK AYURVEDIC MEDICAL COLLEGE AND HOSPITAL RESEARCH CENTRE
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Introduction
✓ Terminal part of GIT
✓ Location - Below the level of pelvic diaphragm
✓ Sacuulations and Taeniae - Absent
Length, Extent and Directions
✓ 3.8 cm long Extension - From Anorectal Junction to the Anus Surrounded by inner involuntary and outer voluntary
Sphincters-
✓ Anorectal Junction - Forward convexity of perineal flexure of rectum
✓ Anus - Surface opening-4 cm below and infront of the tip of the coccyx in the cleft between two buttocks
✓ Surrounding skin is pigmented and contains a large number of apocrine glands
Relations of the Anal Canal
Anteriorly
In both sexes - Perineal body
✓ In Males - Membranous urethra
and bulb of Penis
✓ In Female - Lower end of Vagina
Posteriorly
Anococcygeal ligament
Tip of the соссух
Laterally - Ischioanal Fossa
All round -Surrounded by sphincter muscles
Interior of Anal Canal
Divided into 3 parts -
* Upper Mucous Part
* Middle Part / Transistional Zone / Pecten
* Lower Cutaneous Part
Interior of Anal Canal
✓ 15 mm long
✓ Lined by Mucous Membrane
✓ Endodermal in origin
Mucous Membrane
✓ V6-10 vertical columns/folds Anal Columns / Morgagni
✓ Lower ends of anal columns are united to each other by short trasverse folds of mucous membrane Anal Valves
✓ Above each Valve - Depression in mucosa - Anal Sinus
✓ Anal Valves - Together - Trasverse Line - Runs all round the anal canal~ Pectinate / Dentate Line
✓ Situated opposite to middle of intetnal Anal Sphincter - The junction of ectodermal and endodermal parts
✓ Anal Valves ocaasionally show Epithelial Projections Anal Papillae
✓ Anal sinuses contain Anal Glands
Middle Part / Transitional Zone /Pecten
✓ 15 mm
✔Also lined by Mucous Membrane but anal columns are absent here
Mucosa has Bluish appearance - dense venous plexus - Lies between it and muscle coat
✔ Mucosa - Less mobile
✔ White line of Hilton
✓ At the level of interval between the subcutaneous part of EAS and the lower border of IAS
✔Marks the lower limit of pecten / stratified sqamous epithelium-thin, pale and glossy, devoid of sweat glands
Lower Cutaneous Part
✓ 8 mm long, lined by true skin, contaning sabceous glands
✓ Epithelium of lowest part resembles that of pigmented skin - Sabaceous glands, sweat glands and hair
Musculature of Anal Canal
Anal Sphincters
1. Internal Anal Sphincter
2. External Anal Sphincter
1. Internal Anal Sphincter
✓ Involuntary
✓ Formed by thickned circular muscle coat
✓ Surrounds the upper 3/4 ths - 30 mm of the anal canal to the white line of Hilton
2. External Anal Sphincter
✓ Voluntary
✓ Made up of striated muscles
✓ Surrounds the whole length of the anal canal
✓ 3 parts - Subcutaneous, Superficial and Deep
Conjoint Longitudinal Coat
✓ Formed by the fusion of the Puborectalis and Longitudinal muscle coat of rectum
✓ Lies between external and internal sphincters
Anorectal Ring
✓ Muscular ring
✓ At the Anorectal Junction
✓ Formation - Puborectalis, uppermost fibers of EAS and the internal sphincter
Surgical Spaces Related to Anal Canal
✔ Ischioanal Space - Lies on each side of the anal canal
✔ Perineal Space - Surrounds the anal canal below the white line - Contains - Lower fibers of EAS, External rectal venous plexus, terminal branches of the inferior rectal venous vesseles and nerves
✓Submucous Space -Lies above the white line between the mucuous membrane and intetnal sphincter- Contain - Internal rectal venous plexus, Lymphatics
Arterial Supply
✓ Above the Pectinate Line
- Superior Rectal Artery
✔Below the Pectinate Line
- Inferior Rectal Artery
Venous Drainage
✓ Internal rectal venous plexus/Haemorrhoidal plexus -Submucosa of the anal canal-Drains mainly into superior rectal vein
✓ External rectal plexus-Outside the muscular coat of rectum and anal canal-lower part-drained by the Inferior rectal vein into internal pudendal vein
✓ Anal veins - Arranged radially around the anal margin
Lymphatic Drainage
✓ Part above the Pectinate Line - Drain with those of the rectum into internal iliac nodes
✓ Vesseles from part below the PectinateLine - Drain into medial group of superficial inguinal nodes
Nerve Supply
✓ Above the Pectinate Line - Autonomic Nerves both sympathetic and parasympathetic
✓ Below the Pectinate Line - Somatic Nerves
✓ Sphinctes - Cotraction - Sympathetic Nerves, Relaxation - Parasympathetic Nerves, External sphincter - inferior rectal nerve and by the perineal branch of 4 th sacral nerve
Histology
✓ Upper 15 mm - Simple / Stratified Columnar
✓ Middle 15 mm - Stratified Squamous without any sweat / sabaceous glands / hair follicles
✓ Lowest 8 mm - Resembles true skin with sweat/sabaceous glands and hair follicles
Development
✓ Upper 15 mm - Primitive anorectal canal
✓ Lower 8 mm Ectodermal invagination i.e. Proctodeum
Clinical Anatomy
✓ Piles/Haemorrhoids
✔ Fistula / Fissure in Ano
✓ Anal Stenosis
✓ Anal Agencies with or without Fistula
Piles/haemorrhoids
Internal piles or true piles are saccular dilatations of the internal rectal venous plexus. They occur above the pectinate line and are, therefore, painless. They bleed profusely during straining at stool. The primary piles occur in 3, 7 and 11 o'clock positions of the anal wall when viewed in the lithotomy position. They are formed by enlargement of the three main radicles of the superior rectal vein which lie in the anal columns, which occupy the left lateral, right posterior, and right anterior positions Varicosities in other positions of the lumen are called secondary piles.
Fissure in ano
Anal fissure is caused by the rupture of one of the anal valves, usually by the passage of dry hard stool in a constipated person. Each valve is lined with mucous membrane above, and with skin below. Because of the involvement of skin, the condition is extremely painful and is associated with marked spasm of the anal sphincters
Fistula in ano:
A fistula is an abnormal. epithelialised track connecting two cavities, or one cavity with the exterior.
Fistula in ano is caused by spontaneous rupture of an abscess around the anus or may follow surgical drainage of the abscess.
Research Paper On Anal Canal :-
Carcinoma of Anal Canal -
Abstract -
Carcinoma of the anal canal accounts for 1.5 percent of digestive-system cancers in the United States, with an estimated 3400 new cases in 2000.1 Thirty years ago, anal cancer was believed to be caused by chronic, local inflammation of the perianal area2,3 and was treated with an abdominoperineal resection, necessitating a permanent colostomy.4 As the result of a series of epidemiologic studies, it is now apparent that the development of anal cancer is associated with infection by human papillomavirus, which is usually sexually transmitted. Moreover, in the majority of patients, the condition can be cured by concurrent chemotherapy.
Citation :
Ryan, D. P., Compton, C. C., & Mayer, R. J. (2000). Carcinoma of the anal canal. New England Journal of Medicine, 342(11), 792-800.
Refrence