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Anorectal anatomy and physiology

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Presentation on theme: "Anorectal anatomy and physiology"— Presentation transcript:

1 Anorectal anatomy and physiology
Surgical anal canal ≈ 5 cm up to the Anorectal ring Anatomic anal canal ≈ 3 cm up to the dentate line

2 The rectum 1/3 division Peritoneal coverage Valves of Houston
Anorectal angle Fascial attachments; lateral ligament, Denonvillier fascia, rectosacral fascia


4 Anorectal anatomy and physiology
Dentate line (pectinate) Anoderm Transitional area Columns of Morgagni Internal hemmorrhoidal plexus

5 Anorectal anatomy and physiology

6 Anatomy of the anal canal
Anal glands Anal sphincters Levator ani Anococcygeal raphi Perianal spaces

7 External sphincter

8 Levator ani

9 Anorectal angle

10 Perianal & perirectal spaces

11 Blood supply of the anorectum
Portal circulation; inferior mesenteric artery → superior rectal artery Systemic circulation; middle rectal artery, inferior rectal artery, middle sacral artery

12 Blood supply

13 Venous drainage

14 Lymphatic drainage of anus& rectum
Perirectal nodes Inferior mesenteric nodes Internal iliac nodes Superficial inguinal nodes

15 Lymphatic drainage of rectum

16 Lymphatic drainage of anus

17 Nerve supply of the rectum
Sympathetic L1-3 Parasympathetic S2-4 (nervi ergentes) The hypogastric plexus Pelvic plexus

18 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

19 Nerve supply

20 Physiology of defecation
Reflex Sensation; receptive relaxation of the rectum, anal sampling, rectoanal reflex Center; S2-4, cortical Effectors; sphincters, rectal contraction, abdominal muscles, levator

21 Physiology of defecation

22 Continence mechanism Sensory function; proprioception, touch
Rectal reservoir function Internal sphincter; involuntary, resting tone External sphincter; voluntary, squeeze pressure Levator ani Anorectal angle Anal cushions

23 Anal incontinence types
Major; solid feces Minor; gas, liquid stools, night soiling

24 Anal incontinence Causes
Structural damage; Rectal disease Sphincter injury; birth trauma , surgery …. Neurologic ; Idiopathic

25 Anal incontinence diagnosis
History Rectal examination; tone, squeeze pressure , soilage, …. Endoscopy Endoanal U/S Manometry Nerve studies

26 Endoanal Ultrasonography

27 Anal incontinence Treatment
Diet and drugs Biofeedback Sphincteroplasty Gracilis flap ± electrical stimulator Sacral nerve stimulation= neuromodulation Artificial anal sphincter colostomy

28 Sphincteroplasty

29 Artificial anal sphincter

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