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

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

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

Anorectal anatomy and physiology

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

External sphincter

Levator ani

Anorectal angle

Perianal & perirectal spaces

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

Blood supply

Venous drainage

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

Lymphatic drainage of rectum

Lymphatic drainage of anus

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

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

Nerve supply

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

Physiology of defecation

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

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

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

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

Endoanal Ultrasonography

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

Sphincteroplasty

Artificial anal sphincter