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

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 incontinencetypes

Major; solid feces Minor; gas, liquid stools, night soiling

Anal incontinenceCauses

Structural damage; Rectal disease Sphincter injury; birth trauma , surgery ….

Neurologic ; Idiopathic

Anal incontinencediagnosis

History Rectal examination; tone, squeeze pressure ,

soilage, …. Endoscopy Endoanal U/S Manometry Nerve studies

Endoanal Ultrasonography

Anal incontinenceTreatment

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

Sphincteroplasty

Artificial anal sphincter